CVE-2021-20181
published 2021-05-13CVE-2021-20181: A race condition flaw was found in the 9pfs server implementation of QEMU up to and including 5.2.0. This flaw allows a malicious 9p client to cause a…
PriorityP336high7.5CVSS 3.1
AVLACHPRHUINSCCHIHAH
EPSS
0.32%
24.0th percentile
A race condition flaw was found in the 9pfs server implementation of QEMU up to and including 5.2.0. This flaw allows a malicious 9p client to cause a use-after-free error, potentially escalating their privileges on the system. The highest threat from this vulnerability is to confidentiality, integrity as well as system availability.
Affected
14 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | debian_linux | — | — |
| debian | debian_linux | — | — |
| debian | qemu | < qemu 1:5.2+dfsg-4 (bookworm) | qemu 1:5.2+dfsg-4 (bookworm) |
| msrc | cm1_qemu-kvm_4.2.0-33_on_cbl_mariner_1.0 | — | — |
| qemu | qemu | <= 5.2.0 | — |
| qemu | qemu | — | — |
| qemu | qemu | >= 0 < 1:5.2+dfsg-4 | 1:5.2+dfsg-4 |
| qemu | qemu | >= 0 < 1:5.2+dfsg-4 | 1:5.2+dfsg-4 |
| qemu | qemu | >= 0 < 1:5.2+dfsg-4 | 1:5.2+dfsg-4 |
| qemu | qemu | >= 0 < 1:5.2+dfsg-4 | 1:5.2+dfsg-4 |
| qemu | qemu | >= 0 < 1:2.5+dfsg-5ubuntu10.49 | 1:2.5+dfsg-5ubuntu10.49 |
| qemu | qemu | >= 0 < 1:2.11+dfsg-1ubuntu7.35 | 1:2.11+dfsg-1ubuntu7.35 |
| qemu | qemu | >= 0 < 1:4.2-3ubuntu6.12 | 1:4.2-3ubuntu6.12 |
| ubuntu | qemu | — | — |
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
nvdv2.06.9MEDIUMAV:L/AC:M/Au:N/C:C/I:C/A:C
osv7.5HIGH
vendor_debian7.5HIGH
vendor_msrc7.5HIGH
vendor_redhat7.5HIGH
vendor_ubuntu3.8LOW
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Ubuntu
QEMU regression
vendor_ubuntu·2026-06-28·CVSS 3.8
CVE-2020-11947 [LOW] QEMU regression
Title: QEMU regression
Summary: USN-8412-1 introduced a regression in QEMU
USN-8412-1 fixed vulnerabilities QEMU. On Ubuntu 20.04 LTS, the fix for
CVE-2024-4467 was incomplete and prevented the creation of boot volumes
from qcow2 images. This update fixes the problem.
We apologize for the inconvenience.
Original advisory details:
Felipe Franciosi, Raphael Norwitz, and Peter Turschmid discovered that the
iSCSI block driver in QEMU incorrectly handled certain responses from an
iSCSI server. A remote attacker could possibly use this issue to cause
QEMU to crash, resulting in a denial of service, or possibly execute
arbitrary code. This issue only affected Ubuntu 14.04 LTS. (CVE-2020-1711)
It was discovered that the iSCSI block driver in QEMU incorrectly handled
certain memory operations
Ubuntu
QEMU vulnerabilities
vendor_ubuntu·2026-06-09·CVSS 3.8
CVE-2021-3416 [LOW] QEMU vulnerabilities
Title: QEMU vulnerabilities
Summary: Several security issues were fixed in QEMU.
Felipe Franciosi, Raphael Norwitz, and Peter Turschmid discovered that the
iSCSI block driver in QEMU incorrectly handled certain responses from an
iSCSI server. A remote attacker could possibly use this issue to cause QEMU
to crash, resulting in a denial of service, or possibly execute arbitrary
code. This issue only affected Ubuntu 14.04 LTS. (CVE-2020-1711)
It was discovered that the iSCSI block driver in QEMU incorrectly handled
certain memory operations, leading to a heap-based buffer over-read. An
attacker could possibly use this issue to expose sensitive information from
the host. This issue only affected Ubuntu 14.04 LTS. (CVE-2020-11947)
Ziming Zhang discovered that the SM501 display driver in QEM
Microsoft
A race condition flaw was found in the 9pfs server implementation of QEMU up to and including 5.2.0. This flaw allows a malicious 9p client to cause a use-after-free error potentially escalating their
vendor_msrc·2021-05-11·CVSS 7.5
CVE-2021-20181 [HIGH] CWE-362 A race condition flaw was found in the 9pfs server implementation of QEMU up to and including 5.2.0. This flaw allows a malicious 9p client to cause a use-after-free error potentially escalating their
A race condition flaw was found in the 9pfs server implementation of QEMU up to and including 5.2.0. This flaw allows a malicious 9p client to cause a use-after-free error potentially escalating their privileges on the system. The highest threat from this vulnerability is to confidentiality integrity as well as system availability.
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
Ubuntu
QEMU vulnerabilities
vendor_ubuntu·2021-02-08·CVSS 3.8
CVE-2020-15859 [LOW] QEMU vulnerabilities
Title: QEMU vulnerabilities
Summary: Several security issues were fixed in QEMU.
It was discovered that QEMU incorrectly handled memory in iSCSI emulation.
An attacker inside the guest could possibly use this issue to obtain
sensitive information. This issue only affected Ubuntu 16.04 LTS, Ubuntu
18.04 LTS, and Ubuntu 20.04 LTS. (CVE-2020-11947)
Alexander Bulekov discovered that QEMU incorrectly handled Intel e1000e
emulation. An attacker inside the guest could use this issue to cause QEMU
to crash, resulting in a denial of service. (CVE-2020-15859)
Alexander Bulekov discovered that QEMU incorrectly handled memory region
cache. An attacker inside the guest could use this issue to cause QEMU to
crash, resulting in a denial of service. This issue only affected Ubuntu
20.04 LTS, and Ubunt
Red Hat
qemu: 9pfs: TOCTOU privilege escalation vulnerability
vendor_redhat·2021-01-14·CVSS 7.5
CVE-2021-20181 [HIGH] CWE-367 qemu: 9pfs: TOCTOU privilege escalation vulnerability
qemu: 9pfs: TOCTOU privilege escalation vulnerability
A race condition flaw was found in the 9pfs server implementation of QEMU up to and including 5.2.0. This flaw allows a malicious 9p client to cause a use-after-free error, potentially escalating their privileges on the system. The highest threat from this vulnerability is to confidentiality, integrity as well as system availability.
A race condition flaw was found in the 9pfs server implementation of QEMU. This flaw allows a malicious 9p client to cause a use-after-free error, potentially escalating their privileges on the system. The highest threat from this vulnerability is to confidentiality, integrity as well as system availability.
Statement: This issue does not affect the versions of `qemu-kvm` as shipped with Red Hat products
Debian
CVE-2021-20181: qemu - A race condition flaw was found in the 9pfs server implementation of QEMU up to ...
vendor_debian·2021·CVSS 7.5
CVE-2021-20181 [HIGH] CVE-2021-20181: qemu - A race condition flaw was found in the 9pfs server implementation of QEMU up to ...
A race condition flaw was found in the 9pfs server implementation of QEMU up to and including 5.2.0. This flaw allows a malicious 9p client to cause a use-after-free error, potentially escalating their privileges on the system. The highest threat from this vulnerability is to confidentiality, integrity as well as system availability.
Scope: local
bookworm: resolved (fixed in 1:5.2+dfsg-4)
bullseye: resolved (fixed in 1:5.2+dfsg-4)
forky: resolved (fixed in 1:5.2+dfsg-4)
sid: resolved (fixed in 1:5.2+dfsg-4)
trixie: resolved (fixed in 1:5.2+dfsg-4)
GHSA
GHSA-mq7v-47j3-rc24: A race condition flaw was found in the 9pfs server implementation of QEMU up to and including 5
ghsa_unreviewed·2022-05-24
CVE-2021-20181 [HIGH] CWE-362 GHSA-mq7v-47j3-rc24: A race condition flaw was found in the 9pfs server implementation of QEMU up to and including 5
A race condition flaw was found in the 9pfs server implementation of QEMU up to and including 5.2.0. This flaw allows a malicious 9p client to cause a use-after-free error, potentially escalating their privileges on the system. The highest threat from this vulnerability is to confidentiality, integrity as well as system availability.
OSV
CVE-2021-20181: A race condition flaw was found in the 9pfs server implementation of QEMU up to and including 5
osv·2021-05-13·CVSS 7.5
CVE-2021-20181 [HIGH] CVE-2021-20181: A race condition flaw was found in the 9pfs server implementation of QEMU up to and including 5
A race condition flaw was found in the 9pfs server implementation of QEMU up to and including 5.2.0. This flaw allows a malicious 9p client to cause a use-after-free error, potentially escalating their privileges on the system. The highest threat from this vulnerability is to confidentiality, integrity as well as system availability.
OSV
qemu vulnerabilities
osv·2021-02-08·CVSS 3.8
CVE-2020-11947 [LOW] qemu vulnerabilities
qemu vulnerabilities
It was discovered that QEMU incorrectly handled memory in iSCSI emulation.
An attacker inside the guest could possibly use this issue to obtain
sensitive information. This issue only affected Ubuntu 16.04 LTS, Ubuntu
18.04 LTS, and Ubuntu 20.04 LTS. (CVE-2020-11947)
Alexander Bulekov discovered that QEMU incorrectly handled Intel e1000e
emulation. An attacker inside the guest could use this issue to cause QEMU
to crash, resulting in a denial of service. (CVE-2020-15859)
Alexander Bulekov discovered that QEMU incorrectly handled memory region
cache. An attacker inside the guest could use this issue to cause QEMU to
crash, resulting in a denial of service. This issue only affected Ubuntu
20.04 LTS, and Ubuntu 20.10. (CVE-2020-27821)
Cheol-woo Myung discovered that QE
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
https://bugzilla.redhat.com/show_bug.cgi?id=1927007https://lists.debian.org/debian-lts-announce/2021/02/msg00024.htmlhttps://lists.debian.org/debian-lts-announce/2022/09/msg00008.htmlhttps://security.netapp.com/advisory/ntap-20210720-0009/https://www.zerodayinitiative.com/advisories/ZDI-21-159/https://bugzilla.redhat.com/show_bug.cgi?id=1927007https://lists.debian.org/debian-lts-announce/2021/02/msg00024.htmlhttps://lists.debian.org/debian-lts-announce/2022/09/msg00008.htmlhttps://security.netapp.com/advisory/ntap-20210720-0009/https://www.zerodayinitiative.com/advisories/ZDI-21-159/
2021-05-13
Published