CVE-2020-26541
published 2020-10-02CVE-2020-26541: The Linux kernel through 5.8.13 does not properly enforce the Secure Boot Forbidden Signature Database (aka dbx) protection mechanism. This affects…
PriorityP425medium6.5CVSS 3.1
AVLACLPRHUIRSUCHIHAH
EPSS
0.53%
41.7th percentile
The Linux kernel through 5.8.13 does not properly enforce the Secure Boot Forbidden Signature Database (aka dbx) protection mechanism. This affects certs/blacklist.c and certs/system_keyring.c.
Affected
10 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | linux | < linux 5.14.6-1 (bookworm) | linux 5.14.6-1 (bookworm) |
| linux | linux_kernel | <= 5.8.13 | — |
| linux | linux_kernel | >= 0 < 5.10.70-1 | 5.10.70-1 |
| linux | linux_kernel | >= 0 < 5.14.6-1 | 5.14.6-1 |
| linux | linux_kernel | >= 0 < 5.14.6-1 | 5.14.6-1 |
| linux | linux_kernel | >= 0 < 5.14.6-1 | 5.14.6-1 |
| linux | linux_kernel | >= 0 < 5.4.0-92.103 | 5.4.0-92.103 |
| linux | linux_kernel | >= 0 < 5.4.0-94.106 | 5.4.0-94.106 |
| msrc | cm1_kernel_5.10.57.1-1_on_cbl_mariner_1.0 | — | — |
| paloalto | pan-os | — | — |
CVSS provenance
nvdv3.16.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H
nvdv2.06.9MEDIUMAV:L/AC:M/Au:N/C:C/I:C/A:C
osv7.8HIGH
vendor_ubuntu7.8HIGH
vendor_debian6.5MEDIUM
vendor_msrc6.5MEDIUM
vendor_redhat6.5MEDIUM
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Palo Alto
PAN-SA-2024-0001 Informational Bulletin: Impact of OSS CVEs in PAN-OS
vendor_paloalto·2024-02-14·CVSS 9.8
CVE-2017-18342 [CRITICAL] PAN-SA-2024-0001 Informational Bulletin: Impact of OSS CVEs in PAN-OS
PAN-SA-2024-0001 Informational Bulletin: Impact of OSS CVEs in PAN-OS
The Palo Alto Networks Product Security Assurance team has evaluated the following open source software (OSS) CVEs as they relate to PAN-OS software. While PAN-OS software may include the
CVEs: CVE-2017-18342, CVE-2017-8923, CVE-2017-9120, CVE-2019-1551, CVE-2019-16865, CVE-2019-16905, CVE-2019-19523, CVE-2019-19528, CVE-2019-19911, CVE-2020-0404, CVE-2020-0431, CVE-2020-0466, CVE-2020-10379, CVE-2020-11538, CVE-2020-11608, CVE-2020-12114, CVE-2020-12321, CVE-2020-12362, CVE-2020-12363, CVE-2020-12364, CVE-2020-13757, CVE-2020-14314, CVE-2020-14351, CVE-2020-15778, CVE-2020-1967, CVE-2020-24394, CVE-2020-24504, CVE-2020-25211, CVE-2020-25212, CVE-2020-25284, CVE-2020-25285, CVE-2020-25717, CVE-2020-26541, CVE-2020-2715
Ubuntu
Linux kernel regression
vendor_ubuntu·2022-01-12·CVSS 6.5
[MEDIUM] Linux kernel regression
Title: Linux kernel regression
Summary: USN-5210-1 introduced a regression in the Linux kernel.
USN-5210-1 fixed vulnerabilities in the Linux kernel. Unfortunately,
that update introduced a regression that caused failures to boot in
environments with AMD Secure Encrypted Virtualization (SEV) enabled.
This update fixes the problem.
We apologize for the inconvenience.
Original advisory details:
Nadav Amit discovered that the hugetlb implementation in the Linux kernel
did not perform TLB flushes under certain conditions. A local attacker
could use this to leak or alter data from other processes that use huge
pages. (CVE-2021-4002)
It was discovered that the Linux kernel did not properly enforce certain
types of entries in the Secure Boot Forbidden Signature Database (aka dbx)
protection
Ubuntu
Linux kernel vulnerabilities
vendor_ubuntu·2022-01-06·CVSS 6.5
CVE-2021-4002 [MEDIUM] Linux kernel vulnerabilities
Title: Linux kernel vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Nadav Amit discovered that the hugetlb implementation in the Linux kernel
did not perform TLB flushes under certain conditions. A local attacker
could use this to leak or alter data from other processes that use huge
pages. (CVE-2021-4002)
It was discovered that the Linux kernel did not properly enforce certain
types of entries in the Secure Boot Forbidden Signature Database (aka dbx)
protection mechanism. An attacker could use this to bypass UEFI Secure Boot
restrictions. (CVE-2020-26541)
It was discovered that a race condition existed in the overlay file system
implementation in the Linux kernel. A local attacker could use this to
cause a denial of service (system crash). (CVE-2021-20
Ubuntu
Linux kernel (Azure) vulnerabilities
vendor_ubuntu·2021-10-21·CVSS 7.8
CVE-2021-22543 [HIGH] Linux kernel (Azure) vulnerabilities
Title: Linux kernel (Azure) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that the f2fs file system in the Linux kernel did not
properly validate metadata in some situations. An attacker could use this
to construct a malicious f2fs image that, when mounted and operated on,
could cause a denial of service (system crash) or possibly execute
arbitrary code. (CVE-2019-19449)
It was discovered that the Linux kernel did not properly enforce certain
types of entries in the Secure Boot Forbidden Signature Database (aka dbx)
protection mechanism. An attacker could use this to bypass UEFI Secure Boot
restrictions. (CVE-2020-26541)
It was discovered that the KVM hypervisor implementation for AMD processors
in the Linux kernel did not ensure eno
Ubuntu
Linux kernel (OEM) vulnerabilities
vendor_ubuntu·2021-10-06·CVSS 6.5
CVE-2021-22543 [MEDIUM] Linux kernel (OEM) vulnerabilities
Title: Linux kernel (OEM) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Valentina Palmiotti discovered that the io_uring subsystem in the Linux
kernel could be coerced to free adjacent memory. A local attacker could use
this to execute arbitrary code. (CVE-2021-41073)
It was discovered that the Linux kernel did not properly enforce certain
types of entries in the Secure Boot Forbidden Signature Database (aka dbx)
protection mechanism. An attacker could use this to bypass UEFI Secure Boot
restrictions. (CVE-2020-26541)
It was discovered that the KVM hypervisor implementation in the Linux
kernel did not properly perform reference counting in some situations,
leading to a use-after-free vulnerability. An attacker who could start and
control a VM could po
Ubuntu
Linux kernel vulnerabilities
vendor_ubuntu·2021-09-08·CVSS 6.5
CVE-2021-3612 [MEDIUM] Linux kernel vulnerabilities
Title: Linux kernel vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
Maxim Levitsky and Paolo Bonzini discovered that the KVM hypervisor
implementation for AMD processors in the Linux kernel allowed a guest VM to
disable restrictions on VMLOAD/VMSAVE in a nested guest. An attacker in a
guest VM could use this to read or write portions of the host's physical
memory. (CVE-2021-3656)
Maxim Levitsky discovered that the KVM hypervisor implementation for AMD
processors in the Linux kernel did not properly prevent a guest VM from
enabling AVIC in nested guest VMs. An attacker in a guest VM could use this
to write to portions of the host's physical memory. (CVE-2021-3653)
It was discovered that the Linux kernel did not properly enforce certain
types of entries i
Microsoft
The Linux kernel through 5.8.13 does not properly enforce the Secure Boot Forbidden Signature Database (aka dbx) protection mechanism. This affects certs/blacklist.c and certs/system_keyring.c.
vendor_msrc·2020-10-13·CVSS 6.5
CVE-2020-26541 [MEDIUM] The Linux kernel through 5.8.13 does not properly enforce the Secure Boot Forbidden Signature Database (aka dbx) protection mechanism. This affects certs/blacklist.c and certs/system_keyring.c.
The Linux kernel through 5.8.13 does not properly enforce the Secure Boot Forbidden Signature Database (aka dbx) protection mechanism. This affects certs/blacklist.c and certs/system_keyring.c.
FAQ: Is Azure Linux the only Microsoft product that includes this open-source library and is therefore potentially affected by this vulnerability?
One of the main benefits to our customers who choose to use the Azure Linux distro is the commitment to keep it up to date with the most recent and most secure versions of the open source libraries with which the distro is composed. Microsoft is committed to transparency in this work which is why we began publishing CSAF/VEX in October 2025. See this blog post for more information. If impact to additional products is identified, we will update the CVE to
Red Hat
kernel: security bypass in certs/blacklist.c and certs/system_keyring.c
vendor_redhat·2020-09-15·CVSS 6.5
CVE-2020-26541 [MEDIUM] CWE-347 kernel: security bypass in certs/blacklist.c and certs/system_keyring.c
kernel: security bypass in certs/blacklist.c and certs/system_keyring.c
The Linux kernel through 5.8.13 does not properly enforce the Secure Boot Forbidden Signature Database (aka dbx) protection mechanism. This affects certs/blacklist.c and certs/system_keyring.c.
A flaw was found in the Linux kernel in certs/blacklist.c, When signature entries for EFI_CERT_X509_GUID are contained in the Secure Boot Forbidden Signature Database, the entries are skipped. This can cause a security threat and breach system integrity, confidentiality and even lead to a denial of service problem.
Mitigation: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread i
Debian
CVE-2020-26541: linux - The Linux kernel through 5.8.13 does not properly enforce the Secure Boot Forbid...
vendor_debian·2020·CVSS 6.5
CVE-2020-26541 [MEDIUM] CVE-2020-26541: linux - The Linux kernel through 5.8.13 does not properly enforce the Secure Boot Forbid...
The Linux kernel through 5.8.13 does not properly enforce the Secure Boot Forbidden Signature Database (aka dbx) protection mechanism. This affects certs/blacklist.c and certs/system_keyring.c.
Scope: local
bookworm: resolved (fixed in 5.14.6-1)
bullseye: resolved (fixed in 5.10.70-1)
forky: resolved (fixed in 5.14.6-1)
sid: resolved (fixed in 5.14.6-1)
trixie: resolved (fixed in 5.14.6-1)
GHSA
GHSA-f823-qm69-5873: The Linux kernel through 5
ghsa_unreviewed·2022-05-24
CVE-2020-26541 [MEDIUM] GHSA-f823-qm69-5873: The Linux kernel through 5
The Linux kernel through 5.8.13 does not properly enforce the Secure Boot Forbidden Signature Database (aka dbx) protection mechanism. This affects certs/blacklist.c and certs/system_keyring.c.
OSV
linux, linux-gcp, linux-gcp-5.4, linux-hwe-5.4 regression
osv·2022-01-12·CVSS 6.5
[MEDIUM] linux, linux-gcp, linux-gcp-5.4, linux-hwe-5.4 regression
linux, linux-gcp, linux-gcp-5.4, linux-hwe-5.4 regression
USN-5210-1 fixed vulnerabilities in the Linux kernel. Unfortunately,
that update introduced a regression that caused failures to boot in
environments with AMD Secure Encrypted Virtualization (SEV) enabled.
This update fixes the problem.
We apologize for the inconvenience.
Original advisory details:
Nadav Amit discovered that the hugetlb implementation in the Linux kernel
did not perform TLB flushes under certain conditions. A local attacker
could use this to leak or alter data from other processes that use huge
pages. (CVE-2021-4002)
It was discovered that the Linux kernel did not properly enforce certain
types of entries in the Secure Boot Forbidden Signature Database (aka dbx)
protection mechanism. An attacker could use this
OSV
linux, linux-aws, linux-aws-5.4, linux-azure, linux-azure-5.4, linux-bluefield, linux-gcp, linux-gcp-5.4, linux-gke, linux-gke-5.4, linux-gkeop, linux-gkeop-5.4, linux-hwe-5.4, linux-ibm, linux-kvm, l
osv·2022-01-06·CVSS 6.5
[MEDIUM] linux, linux-aws, linux-aws-5.4, linux-azure, linux-azure-5.4, linux-bluefield, linux-gcp, linux-gcp-5.4, linux-gke, linux-gke-5.4, linux-gkeop, linux-gkeop-5.4, linux-hwe-5.4, linux-ibm, linux-kvm, l
linux, linux-aws, linux-aws-5.4, linux-azure, linux-azure-5.4, linux-bluefield, linux-gcp, linux-gcp-5.4, linux-gke, linux-gke-5.4, linux-gkeop, linux-gkeop-5.4, linux-hwe-5.4, linux-ibm, linux-kvm, linux-oracle, linux-oracle-5.4, linux-raspi, linux-raspi-5.4 vulnerabilities
Nadav Amit discovered that the hugetlb implementation in the Linux kernel
did not perform TLB flushes under certain conditions. A local attacker
could use this to leak or alter data from other processes that use huge
pages. (CVE-2021-4002)
It was discovered that the Linux kernel did not properly enforce certain
types of entries in the Secure Boot Forbidden Signature Database (aka dbx)
protection mechanism. An attacker could use this to bypass UEFI Secure Boot
restrictions. (CVE-2020-26541)
It was discovered that a r
OSV
linux-azure-5.8 vulnerabilities
osv·2021-10-21·CVSS 7.8
CVE-2019-19449 [HIGH] linux-azure-5.8 vulnerabilities
linux-azure-5.8 vulnerabilities
It was discovered that the f2fs file system in the Linux kernel did not
properly validate metadata in some situations. An attacker could use this
to construct a malicious f2fs image that, when mounted and operated on,
could cause a denial of service (system crash) or possibly execute
arbitrary code. (CVE-2019-19449)
It was discovered that the Linux kernel did not properly enforce certain
types of entries in the Secure Boot Forbidden Signature Database (aka dbx)
protection mechanism. An attacker could use this to bypass UEFI Secure Boot
restrictions. (CVE-2020-26541)
It was discovered that the KVM hypervisor implementation for AMD processors
in the Linux kernel did not ensure enough processing time was given to
perform cleanups of large SEV VMs. A local at
OSV
linux-oem-5.10 vulnerabilities
osv·2021-10-06·CVSS 6.5
CVE-2021-41073 [MEDIUM] linux-oem-5.10 vulnerabilities
linux-oem-5.10 vulnerabilities
Valentina Palmiotti discovered that the io_uring subsystem in the Linux
kernel could be coerced to free adjacent memory. A local attacker could use
this to execute arbitrary code. (CVE-2021-41073)
It was discovered that the Linux kernel did not properly enforce certain
types of entries in the Secure Boot Forbidden Signature Database (aka dbx)
protection mechanism. An attacker could use this to bypass UEFI Secure Boot
restrictions. (CVE-2020-26541)
It was discovered that the KVM hypervisor implementation in the Linux
kernel did not properly perform reference counting in some situations,
leading to a use-after-free vulnerability. An attacker who could start and
control a VM could possibly use this to expose sensitive information or
execute arbitrary code. (C
OSV
linux, linux-aws, linux-aws-5.11, linux-azure, linux-azure-5.11, linux-gcp, linux-hwe-5.11, linux-kvm, linux-oracle, linux-oracle-5.11, linux-raspi vulnerabilities
osv·2021-09-08·CVSS 6.5
CVE-2021-3656 [MEDIUM] linux, linux-aws, linux-aws-5.11, linux-azure, linux-azure-5.11, linux-gcp, linux-hwe-5.11, linux-kvm, linux-oracle, linux-oracle-5.11, linux-raspi vulnerabilities
linux, linux-aws, linux-aws-5.11, linux-azure, linux-azure-5.11, linux-gcp, linux-hwe-5.11, linux-kvm, linux-oracle, linux-oracle-5.11, linux-raspi vulnerabilities
Maxim Levitsky and Paolo Bonzini discovered that the KVM hypervisor
implementation for AMD processors in the Linux kernel allowed a guest VM to
disable restrictions on VMLOAD/VMSAVE in a nested guest. An attacker in a
guest VM could use this to read or write portions of the host's physical
memory. (CVE-2021-3656)
Maxim Levitsky discovered that the KVM hypervisor implementation for AMD
processors in the Linux kernel did not properly prevent a guest VM from
enabling AVIC in nested guest VMs. An attacker in a guest VM could use this
to write to portions of the host's physical memory. (CVE-2021-3653)
It was discovered that the Li
Kernel
Merge tag 'keys-cve-2020-26541-v3' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
kernel_security·2021-04-26·CVSS 6.5
CVE-2020-26541 [MEDIUM] Merge tag 'keys-cve-2020-26541-v3' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Merge tag 'keys-cve-2020-26541-v3' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull x509 dbx/mokx UEFI support from David Howells:
"Here's a set of patches from Eric Snowberg[1] that add support for
EFI_CERT_X509_GUID entries in the dbx and mokx UEFI tables (such
entries cause matching certificates to be rejected).
These are currently ignored and only the hash entries are made use of.
Additionally Eric included his patches to allow such certificates to
be preloaded.
These patches deal with CVE-2020-26541.
To quote Eric:
'This is the fifth patch series for adding support for
EFI_CERT_X509_GUID entries [2]. It has been expanded to not only
include dbx entries but also entries in the mokx. Additionally
my series to preload these certificate [3] has also been
includ
Kernel
certs: Add EFI_CERT_X509_GUID support for dbx entries
kernel_security·2021-01-22·CVSS 6.5
CVE-2020-26541 [MEDIUM] certs: Add EFI_CERT_X509_GUID support for dbx entries
certs: Add EFI_CERT_X509_GUID support for dbx entries
This fixes CVE-2020-26541.
The Secure Boot Forbidden Signature Database, dbx, contains a list of now
revoked signatures and keys previously approved to boot with UEFI Secure
Boot enabled. The dbx is capable of containing any number of
EFI_CERT_X509_SHA256_GUID, EFI_CERT_SHA256_GUID, and EFI_CERT_X509_GUID
entries.
Currently when EFI_CERT_X509_GUID are contained in the dbx, the entries are
skipped.
Add support for EFI_CERT_X509_GUID dbx entries. When a EFI_CERT_X509_GUID
is found, it is added as an asymmetrical key to the .blacklist keyring.
Anytime the .platform keyring is used, the keys in the .blacklist keyring
are referenced, if a matching key is found, the key will be rejected.
[DH: Made the following changes:
- Added to have a
OSV
CVE-2020-26541: The Linux kernel through 5
osv·2020-10-02·CVSS 6.5
CVE-2020-26541 [MEDIUM] CVE-2020-26541: The Linux kernel through 5
The Linux kernel through 5.8.13 does not properly enforce the Secure Boot Forbidden Signature Database (aka dbx) protection mechanism. This affects certs/blacklist.c and certs/system_keyring.c.
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2020-26541 kernel: security bypass in certs/blacklist.c and certs/system_keyring.c [fedora-all]
bugzilla·2020-10-08·CVSS 6.5
CVE-2020-26541 [MEDIUM] CVE-2020-26541 kernel: security bypass in certs/blacklist.c and certs/system_keyring.c [fedora-all]
CVE-2020-26541 kernel: security bypass in certs/blacklist.c and certs/system_keyring.c [fedora-all]
This is an automatically created tracking bug! It was created to ensure
that one or more security vulnerabilities are fixed in affected versions
of fedora-all.
For comments that are specific to the vulnerability please use bugs filed
against the "Security Response" product referenced in the "Blocks" field.
For more information see:
http://fedoraproject.org/wiki/Security/TrackingBugs
When submitting as an update, use the fedpkg template provided in the next
comment(s). This will include the bug IDs of this tracking bug as well as
the relevant top-level CVE bugs.
Please also mention the CVE IDs being fixed in the RPM changelog and the
fedpkg commit message.
NOTE: this issue affects multi
Bugzilla
CVE-2020-26541 kernel: security bypass in certs/blacklist.c and certs/system_keyring.c
bugzilla·2020-10-08·CVSS 6.5
CVE-2020-26541 [MEDIUM] CVE-2020-26541 kernel: security bypass in certs/blacklist.c and certs/system_keyring.c
CVE-2020-26541 kernel: security bypass in certs/blacklist.c and certs/system_keyring.c
A flaw was found in the Linux kernel in certs/blacklist.c, When signature entries for EFI_CERT_X509_GUID are contained in the Secure Boot Forbidden Signature Database, the entries are skipped. This can cause a security threat and breach system integrity, confidentiality and even lead to a denial of service problem.
The Linux kernel does not properly enforce the Secure Boot Forbidden Signature Database (aka dbx) protection mechanism.
References:
https://lkml.org/lkml/2020/9/15/1871
Discussion:
Created kernel tracking bugs for this issue:
Affects: fedora-all [bug 1886287]
---
Mitigation:
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Pro
2020-10-02
Published