CVE-2025-31133
published 2025-11-06CVE-2025-31133: runc is a CLI tool for spawning and running containers according to the OCI specification. In versions 1.2.7 and below, 1.3.0-rc.1 through 1.3.1, 1.4.0-rc.1…
PriorityP345high7.8CVSS 3.1
AVLACHPRLUINSCCHIHAH
EPSS
0.67%
47.5th percentile
runc is a CLI tool for spawning and running containers according to the OCI specification. In versions 1.2.7 and below, 1.3.0-rc.1 through 1.3.1, 1.4.0-rc.1 and 1.4.0-rc.2 files, runc would not perform sufficient verification that the source of the bind-mount (i.e., the container's /dev/null) was actually a real /dev/null inode when using the container's /dev/null to mask. This exposes two methods of attack: an arbitrary mount gadget, leading to host information disclosure, host denial of service, container escape, or a bypassing of maskedPaths. This issue is fixed in versions 1.2.8, 1.3.3 and 1.4.0-rc.3.
Affected
18 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | runc | < runc 1.3.3+ds1-2 (forky) | runc 1.3.3+ds1-2 (forky) |
| github.com | opencontainers_runc | >= 0 < 1.2.8 | 1.2.8 |
| github.com | opencontainers_runc | >= 1.0.0-rc3 < 1.2.8 | 1.2.8 |
| github.com | opencontainers_runc | >= 1.3.0-rc.1 < 1.3.3 | 1.3.3 |
| github.com | opencontainers_runc | >= 1.4.0-rc.1 < 1.4.0-rc.3 | 1.4.0-rc.3 |
| github.com | opencontainers_selinux | >= 0 < 1.13.0 | 1.13.0 |
| linuxfoundation | runc | < 1.2.8 | 1.2.8 |
| linuxfoundation | runc | — | — |
| linuxfoundation | runc | — | — |
| linuxfoundation | runc | >= 0 < 1.3.3+ds1-2 | 1.3.3+ds1-2 |
| linuxfoundation | runc | >= 1.0.1 < 1.2.8 | 1.2.8 |
| linuxfoundation | runc | >= 1.3.0 < 1.3.3 | 1.3.3 |
| msrc | azl3_kubernetes_1.30.10-14_on_azure_linux_3.0 | — | — |
| msrc | cbl2_kubernetes_1.28.4-19_on_cbl_mariner_2.0 | — | — |
| msrc | cbl2_moby-runc_1.1.9-9_on_cbl_mariner_2.0 | — | — |
| opencontainers | runc | — | — |
| opencontainers | runc | — | — |
| opencontainers | runc | — | — |
CVSS provenance
nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
nvdv4.07.3HIGHCVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
ghsa7.3HIGH
osv7.5HIGH
vendor_ubuntu7.5HIGH
vendor_debian7.3HIGH
vendor_msrc7.3HIGH
vendor_redhat7.3HIGH
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OSV
runc-app, runc-stable regression
osv·2025-11-24·CVSS 7.5
CVE-2025-31133 [HIGH] runc-app, runc-stable regression
runc-app, runc-stable regression
USN-7851-1 fixed vulnerabilities in runC. The introduction of a new
upstream release has caused regressions in runc-app and runc-stable.
This update fixes the problem.
Original advisory details:
Lei Wang and Li Fubang discovered that runC incorrectly handled masked
paths. An attacker could possibly replace a container's /dev/null
with a symlink to some other procfs file and possibly escape a container.
(CVE-2025-31133)
Lei Wang and Li Fubang discovered that runC incorrectly handled the
/dev/console bind-mounts. An attacker could potentially exploit this issue
to build-mount a symlink and escape a container. (CVE-2025-52565)
Li Fubang and Tõnis Tiigi discovered that the fix for CVE-2019-16884 was
incomplete. An attacker could possibly use this issue to
OSV
Container escape via "masked path" abuse due to mount race conditions in github.com/opencontainers/runc
osv·2025-11-18
CVE-2025-31133 Container escape via "masked path" abuse due to mount race conditions in github.com/opencontainers/runc
Container escape via "masked path" abuse due to mount race conditions in github.com/opencontainers/runc
Container escape via "masked path" abuse due to mount race conditions in github.com/opencontainers/runc
OSV
CVE-2025-52565: runc is a CLI tool for spawning and running containers according to the OCI specification
osv·2025-11-06·CVSS 7.3
CVE-2025-52565 [HIGH] CVE-2025-52565: runc is a CLI tool for spawning and running containers according to the OCI specification
runc is a CLI tool for spawning and running containers according to the OCI specification. Versions 1.0.0-rc3 through 1.2.7, 1.3.0-rc.1 through 1.3.2, and 1.4.0-rc.1 through 1.4.0-rc.2, due to insufficient checks when bind-mounting `/dev/pts/$n` to `/dev/console` inside the container, an attacker can trick runc into bind-mounting paths which would normally be made read-only or be masked onto a path that the attacker can write to. This attack is very similar in concept and application to CVE-2025-31133, except that it attacks a similar vulnerability in a different target (namely, the bind-mount of `/dev/pts/$n` to `/dev/console` as configured for all containers that allocate a console). This happens after `pivot_root(2)`, so this cannot be used to write to host files directly -- however, as
OSV
CVE-2025-31133: runc is a CLI tool for spawning and running containers according to the OCI specification
osv·2025-11-06·CVSS 7.3
CVE-2025-31133 [HIGH] CVE-2025-31133: runc is a CLI tool for spawning and running containers according to the OCI specification
runc is a CLI tool for spawning and running containers according to the OCI specification. In versions 1.2.7 and below, 1.3.0-rc.1 through 1.3.1, 1.4.0-rc.1 and 1.4.0-rc.2 files, runc would not perform sufficient verification that the source of the bind-mount (i.e., the container's /dev/null) was actually a real /dev/null inode when using the container's /dev/null to mask. This exposes two methods of attack: an arbitrary mount gadget, leading to host information disclosure, host denial of service, container escape, or a bypassing of maskedPaths. This issue is fixed in versions 1.2.8, 1.3.3 and 1.4.0-rc.3.
OSV
runc container escape via "masked path" abuse due to mount race conditions
osv·2025-11-05
CVE-2025-31133 [HIGH] runc container escape via "masked path" abuse due to mount race conditions
runc container escape via "masked path" abuse due to mount race conditions
### Impact ###
The OCI runtime specification has a `maskedPaths` feature that allows for files or directories to be "masked" by placing a mount on top of them to conceal their contents. This is primarily intended to protect against privileged users in non-user-namespaced from being able to write to files or access directories that would either provide sensitive information about the host to containers or allow containers to perform destructive or other privileged operations on the host (examples include `/proc/kcore`, `/proc/timer_list`, `/proc/acpi`, and `/proc/keys`).
`maskedPaths` can be used to either mask a directory or a file -- directories are masked using a new read-only `tmpfs` instance that is mounted on
GHSA
runc container escape and denial of service due to arbitrary write gadgets and procfs write redirects
ghsa·2025-11-05·CVSS 7.0
CVE-2025-52881 [HIGH] CWE-363 runc container escape and denial of service due to arbitrary write gadgets and procfs write redirects
runc container escape and denial of service due to arbitrary write gadgets and procfs write redirects
### Impact ###
This attack is primarily a more sophisticated version of CVE-2019-19921, which was a flaw which allowed an attacker to trick runc into writing the LSM process labels for a container process into a dummy `tmpfs` file and thus not apply the correct LSM labels to the container process. The mitigation runc applied for CVE-2019-19921 was fairly limited and effectively only caused runc to verify that when runc writes LSM labels that those labels are actual procfs files.
Rather than using a fake `tmpfs` file for `/proc/self/attr/`, an attacker could instead (through various means) make `/proc/self/attr/` reference a real `procfs` file, but one that would still be a no-op (such a
OSV
runc container escape and denial of service due to arbitrary write gadgets and procfs write redirects
osv·2025-11-05·CVSS 7.0
CVE-2025-52881 [HIGH] runc container escape and denial of service due to arbitrary write gadgets and procfs write redirects
runc container escape and denial of service due to arbitrary write gadgets and procfs write redirects
### Impact ###
This attack is primarily a more sophisticated version of CVE-2019-19921, which was a flaw which allowed an attacker to trick runc into writing the LSM process labels for a container process into a dummy `tmpfs` file and thus not apply the correct LSM labels to the container process. The mitigation runc applied for CVE-2019-19921 was fairly limited and effectively only caused runc to verify that when runc writes LSM labels that those labels are actual procfs files.
Rather than using a fake `tmpfs` file for `/proc/self/attr/`, an attacker could instead (through various means) make `/proc/self/attr/` reference a real `procfs` file, but one that would still be a no-op (such a
OSV
runc container escape with malicious config due to /dev/console mount and related races
osv·2025-11-05·CVSS 7.3
CVE-2025-52565 [HIGH] runc container escape with malicious config due to /dev/console mount and related races
runc container escape with malicious config due to /dev/console mount and related races
### Impact ###
This attack is very similar in concept and application to CVE-2025-31133, except that it attacks a similar vulnerability in a different target (namely, the bind-mount of `/dev/pts/$n` to `/dev/console` as configured for all containers that allocate a console).
In runc version 1.0.0-rc3 and later, due to insufficient checks when bind-mounting `/dev/pts/$n` to `/dev/console` inside the container, an attacker can trick runc into bind-mounting paths which would normally be made read-only or be masked onto a path that the attacker can write to. This happens after `pivot_root(2)`, so this cannot be used to write to host files directly -- however, as with CVE-2025-31133, this can load to denia
GHSA
runc container escape with malicious config due to /dev/console mount and related races
ghsa·2025-11-05·CVSS 7.3
CVE-2025-52565 [HIGH] CWE-363 runc container escape with malicious config due to /dev/console mount and related races
runc container escape with malicious config due to /dev/console mount and related races
### Impact ###
This attack is very similar in concept and application to CVE-2025-31133, except that it attacks a similar vulnerability in a different target (namely, the bind-mount of `/dev/pts/$n` to `/dev/console` as configured for all containers that allocate a console).
In runc version 1.0.0-rc3 and later, due to insufficient checks when bind-mounting `/dev/pts/$n` to `/dev/console` inside the container, an attacker can trick runc into bind-mounting paths which would normally be made read-only or be masked onto a path that the attacker can write to. This happens after `pivot_root(2)`, so this cannot be used to write to host files directly -- however, as with CVE-2025-31133, this can load to denia
GHSA
runc container escape via "masked path" abuse due to mount race conditions
ghsa·2025-11-05
CVE-2025-31133 [HIGH] CWE-363 runc container escape via "masked path" abuse due to mount race conditions
runc container escape via "masked path" abuse due to mount race conditions
### Impact ###
The OCI runtime specification has a `maskedPaths` feature that allows for files or directories to be "masked" by placing a mount on top of them to conceal their contents. This is primarily intended to protect against privileged users in non-user-namespaced from being able to write to files or access directories that would either provide sensitive information about the host to containers or allow containers to perform destructive or other privileged operations on the host (examples include `/proc/kcore`, `/proc/timer_list`, `/proc/acpi`, and `/proc/keys`).
`maskedPaths` can be used to either mask a directory or a file -- directories are masked using a new read-only `tmpfs` instance that is mounted on
OSV
runc-app, runc-stable vulnerabilities
osv·2025-11-04·CVSS 7.5
CVE-2025-31133 [HIGH] runc-app, runc-stable vulnerabilities
runc-app, runc-stable vulnerabilities
Lei Wang and Li Fubang discovered that runC incorrectly handled masked
paths. An attacker could possibly replace a container's /dev/null
with a symlink to some other procfs file and possibly escape a container.
(CVE-2025-31133)
Lei Wang and Li Fubang discovered that runC incorrectly handled the
/dev/console bind-mounts. An attacker could potentially exploit this issue
to build-mount a symlink and escape a container. (CVE-2025-52565)
Li Fubang and Tõnis Tiigi discovered that the fix for CVE-2019-16884 was
incomplete. An attacker could possibly use this issue to cause a denial of
service or escape the container. (CVE-2025-52881)
Ubuntu
runC regression
vendor_ubuntu·2025-11-24·CVSS 7.5
[HIGH] runC regression
Title: runC regression
Summary: USN-7851-1 introduced a regression in runC
USN-7851-1 fixed vulnerabilities in runC. The introduction of a new
upstream release has caused regressions in runc-app and runc-stable.
This update fixes the problem.
Original advisory details:
Lei Wang and Li Fubang discovered that runC incorrectly handled masked
paths. An attacker could possibly replace a container's /dev/null
with a symlink to some other procfs file and possibly escape a container.
(CVE-2025-31133)
Lei Wang and Li Fubang discovered that runC incorrectly handled the
/dev/console bind-mounts. An attacker could potentially exploit this issue
to build-mount a symlink and escape a container. (CVE-2025-52565)
Li Fubang and Tõnis Tiigi discovered that the fix for CVE-2019-16884 was
incomplete. An
Microsoft
runc container escape via "masked path" abuse due to mount race conditions
vendor_msrc·2025-11-11·CVSS 7.3
CVE-2025-31133 [HIGH] CWE-61 runc container escape via "masked path" abuse due to mount race conditions
runc container escape via "masked path" abuse due to mount race conditions
Mariner: Mariner
GitHub_M: GitHub_M
Customer Action Required: Yes
Remediation: CBL-Mariner Releases
Reference: https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade
Red Hat
runc: container escape with malicious config due to /dev/console mount and related races
vendor_redhat·2025-11-05·CVSS 7.3
CVE-2025-52565 [HIGH] CWE-59 runc: container escape with malicious config due to /dev/console mount and related races
runc: container escape with malicious config due to /dev/console mount and related races
runc is a CLI tool for spawning and running containers according to the OCI specification. Versions 1.0.0-rc3 through 1.2.7, 1.3.0-rc.1 through 1.3.2, and 1.4.0-rc.1 through 1.4.0-rc.2, due to insufficient checks when bind-mounting `/dev/pts/$n` to `/dev/console` inside the container, an attacker can trick runc into bind-mounting paths which would normally be made read-only or be masked onto a path that the attacker can write to. This attack is very similar in concept and application to CVE-2025-31133, except that it attacks a similar vulnerability in a different target (namely, the bind-mount of `/dev/pts/$n` to `/dev/console` as configured for all containers that allocate a console). This happens af
Red Hat
runc: container escape via 'masked path' abuse due to mount race conditions
vendor_redhat·2025-11-05·CVSS 7.3
CVE-2025-31133 [HIGH] CWE-59 runc: container escape via 'masked path' abuse due to mount race conditions
runc: container escape via 'masked path' abuse due to mount race conditions
runc is a CLI tool for spawning and running containers according to the OCI specification. In versions 1.2.7 and below, 1.3.0-rc.1 through 1.3.1, 1.4.0-rc.1 and 1.4.0-rc.2 files, runc would not perform sufficient verification that the source of the bind-mount (i.e., the container's /dev/null) was actually a real /dev/null inode when using the container's /dev/null to mask. This exposes two methods of attack: an arbitrary mount gadget, leading to host information disclosure, host denial of service, container escape, or a bypassing of maskedPaths. This issue is fixed in versions 1.2.8, 1.3.3 and 1.4.0-rc.3.
A flaw was found in runc. This flaw exploits an issue with how masked paths are implementedin runc. When mask
Ubuntu
runC vulnerabilities
vendor_ubuntu·2025-11-04·CVSS 7.5
CVE-2025-52565 [HIGH] runC vulnerabilities
Title: runC vulnerabilities
Summary: Several security issues were fixed in runC.
Lei Wang and Li Fubang discovered that runC incorrectly handled masked
paths. An attacker could possibly replace a container's /dev/null
with a symlink to some other procfs file and possibly escape a container.
(CVE-2025-31133)
Lei Wang and Li Fubang discovered that runC incorrectly handled the
/dev/console bind-mounts. An attacker could potentially exploit this issue
to build-mount a symlink and escape a container. (CVE-2025-52565)
Li Fubang and Tõnis Tiigi discovered that the fix for CVE-2019-16884 was
incomplete. An attacker could possibly use this issue to cause a denial of
service or escape the container. (CVE-2025-52881)
Instructions: This update uses a new upstream release, which includes additiona
Debian
CVE-2025-52565: runc - runc is a CLI tool for spawning and running containers according to the OCI spec...
vendor_debian·2025·CVSS 7.3
CVE-2025-52565 [HIGH] CVE-2025-52565: runc - runc is a CLI tool for spawning and running containers according to the OCI spec...
runc is a CLI tool for spawning and running containers according to the OCI specification. Versions 1.0.0-rc3 through 1.2.7, 1.3.0-rc.1 through 1.3.2, and 1.4.0-rc.1 through 1.4.0-rc.2, due to insufficient checks when bind-mounting `/dev/pts/$n` to `/dev/console` inside the container, an attacker can trick runc into bind-mounting paths which would normally be made read-only or be masked onto a path that the attacker can write to. This attack is very similar in concept and application to CVE-2025-31133, except that it attacks a similar vulnerability in a different target (namely, the bind-mount of `/dev/pts/$n` to `/dev/console` as configured for all containers that allocate a console). This happens after `pivot_root(2)`, so this cannot be used to write to host files directly -- however, as
Debian
CVE-2025-31133: runc - runc is a CLI tool for spawning and running containers according to the OCI spec...
vendor_debian·2025·CVSS 7.3
CVE-2025-31133 [HIGH] CVE-2025-31133: runc - runc is a CLI tool for spawning and running containers according to the OCI spec...
runc is a CLI tool for spawning and running containers according to the OCI specification. In versions 1.2.7 and below, 1.3.0-rc.1 through 1.3.1, 1.4.0-rc.1 and 1.4.0-rc.2 files, runc would not perform sufficient verification that the source of the bind-mount (i.e., the container's /dev/null) was actually a real /dev/null inode when using the container's /dev/null to mask. This exposes two methods of attack: an arbitrary mount gadget, leading to host information disclosure, host denial of service, container escape, or a bypassing of maskedPaths. This issue is fixed in versions 1.2.8, 1.3.3 and 1.4.0-rc.3.
Scope: local
bookworm: open
bullseye: open
forky: resolved (fixed in 1.3.3+ds1-2)
sid: resolved (fixed in 1.3.3+ds1-2)
trixie: open
No detection rules found.
No public exploits indexed.
Wiz
Supply Chain Attacks & AI Vulnerabilities: December Cloud Security Update | Wiz
blogs_wiz·2025-12-01·CVSS 10.0
[CRITICAL] Supply Chain Attacks & AI Vulnerabilities: December Cloud Security Update | Wiz
Welcome back! This edition delivers the latest cloud security highlights: key breaches, unique data findings, and must-watch vulnerabilities. Let’s jump in.
🔍 Highlights
Shai-Hulud 2.0: Ongoing Supply Chain Campaign Referencing Shai-Hulud
A new npm supply-chain campaign referencing Shai-Hulud temporarily compromised packages from Zapier, ENS Domains, PostHog, Postman, and others. This wave leveraged temporarily compromised npm maintainer accounts to publish trojanized versions of legitimate packages from major ecosystems. Wiz observed over 25,000 repositories containing secrets across ~350 unique users.
The malicious packages execute code during the preinstall phase, enabling theft of developer and CI/CD secrets and automated propagation to new repositories. Exfiltration is conducted c
Bleepingcomputer
Dangerous runC flaws could allow hackers to escape Docker containers
blogs_bleepingcomputer·2025-11-09·CVSS 7.3
CVE-2025-31133 [HIGH] Dangerous runC flaws could allow hackers to escape Docker containers
## Dangerous runC flaws could allow hackers to escape Docker containers
## Bill Toulas
Three newly disclosed vulnerabilities in the runC container runtime used in Docker and Kubernetes could be exploited to bypass isolation restrictions and get access to the host system.
The security issues, tracked as CVE-2025-31133, CVE-2025-52565, and CVE-2025-52881 (all ), were reported this week and disclosed by SUSE software engineer and Open Container Initiative (OCI) board member Aleksa Sarai .
runC is a universal container runtime and the OCI reference implementation for running containers. It is responsible for low-level operations such as creating the container process, setting up namespaces, mounts, and cgroups that higher-level tools, like Docker and Kubernetes, can call.
An attacker expl
Bugzilla
CVE-2025-31133 runc: container escape via 'masked path' abuse due to mount race conditions
bugzilla·2025-10-17·CVSS 7.3
CVE-2025-31133 [HIGH] CVE-2025-31133 runc: container escape via 'masked path' abuse due to mount race conditions
CVE-2025-31133 runc: container escape via 'masked path' abuse due to mount race conditions
A flaw was found in runc. This flaw exploits an issue with how masked paths are implementedin runc. When masking files, runc will bind-mount the container's /dev/null inode on top of the file. However, if an attacker can replace /dev/null with a symlink to some other procfs file, runc will instead bind-mount the symlink target read-write.
Discussion:
This issue has been addressed in the following products:
Red Hat Enterprise Linux 9
Via RHSA-2025:19927 https://access.redhat.com/errata/RHSA-2025:19927
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 9
Via RHSA-2025:20957 https://access.redhat.com/errata/RHSA-2025:20957
---
This issue has been addressed i
Bugzilla
CVE-2025-52565 runc: container escape with malicious config due to /dev/console mount and related races
bugzilla·2025-10-17·CVSS 7.3
CVE-2025-52565 [HIGH] CVE-2025-52565 runc: container escape with malicious config due to /dev/console mount and related races
CVE-2025-52565 runc: container escape with malicious config due to /dev/console mount and related races
A flaw was found in runc. CVE-2025-52565 is very similar in concept and application toCVE-2025-31133, except that it exploits a flaw in /dev/console
bind-mounts. When creating the /dev/console bind-mount (to /dev/pts/$n), if an attacker replaces /dev/pts/$n with a symlink then runc will bind-mount the symlink target over /dev/console.
Discussion:
This issue has been addressed in the following products:
Red Hat Enterprise Linux 9
Via RHSA-2025:19927 https://access.redhat.com/errata/RHSA-2025:19927
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 9
Via RHSA-2025:20957 https://access.redhat.com/errata/RHSA-2025:20957
---
This issue has been ad
https://github.com/opencontainers/runc/commit/1a30a8f3d921acbbb6a4bb7e99da2c05f8d48522https://github.com/opencontainers/runc/commit/5d7b2424072449872d1cd0c937f2ca25f418eb66https://github.com/opencontainers/runc/commit/8476df83b534a2522b878c0507b3491def48db9fhttps://github.com/opencontainers/runc/commit/db19bbed5348847da433faa9d69e9f90192bfa64https://github.com/opencontainers/runc/security/advisories/GHSA-9493-h29p-rfm2
2025-11-06
Published