CVE-2021-20181: QEMU Plan 9 File System Time-Of-Check Time-Of-Use Privilege Escalation Vulnerability
First published: Tue Feb 09 2021(Updated: )
A flaw was found in QEMU in the way it handles a list of open file descriptors. Improper synchronization of this list can lead to a use-after-free. Reference: <a href="https://bugs.launchpad.net/qemu/+bug/1911666">https://bugs.launchpad.net/qemu/+bug/1911666</a> Upstream patch: <a href="https://git.qemu.org/?p=qemu.git;a=commit;h=89fbea8737e8f7b954745a1ffc4238d377055305">https://git.qemu.org/?p=qemu.git;a=commit;h=89fbea8737e8f7b954745a1ffc4238d377055305</a>
Credit: secalert@redhat.com secalert@redhat.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| QEMU qemu | <=5.2.0 | |
| Debian Debian Linux | =9.0 | |
| Debian Debian Linux | =10.0 | |
| QEMU qemu | ||
| debian/qemu | 1:5.2+dfsg-11+deb11u3 1:5.2+dfsg-11+deb11u2 1:7.2+dfsg-7+deb12u12 1:9.2.0+ds-2 1:9.2.0+ds-5 |
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Reference Links
- https://bugzilla.redhat.com/show_bug.cgi?id=1927007
- https://lists.debian.org/debian-lts-announce/2021/02/msg00024.html
- https://lists.debian.org/debian-lts-announce/2022/09/msg00008.html
- https://security.netapp.com/advisory/ntap-20210720-0009/
- https://www.zerodayinitiative.com/advisories/ZDI-21-159/
- https://launchpad.net/bugs/cve/CVE-2021-20181
- https://bugs.launchpad.net/qemu/+bug/1911666
- https://git.qemu.org/?p=qemu.git;a=commit;h=89fbea8737e8f7b954745a1ffc4238d377055305
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1927009
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1927008
- https://access.redhat.com/security/cve/cve-2021-20181
- https://security-tracker.debian.org/tracker/CVE-2021-20181
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-20181
- https://nvd.nist.gov/vuln/detail/CVE-2021-20181
- https://ubuntu.com/security/CVE-2021-20181
Frequently Asked Questions
What is CVE-2021-20181?
CVE-2021-20181 is a vulnerability in QEMU that allows local attackers to execute arbitrary code on affected installations.
How severe is CVE-2021-20181?
CVE-2021-20181 has a severity rating of 7.5 (High).
Which software is affected by CVE-2021-20181?
QEMU versions up to and including 5.2.0 are affected. Additionally, Debian Linux versions 9.0 and 10.0 are affected as well.
How can an attacker exploit CVE-2021-20181?
To exploit CVE-2021-20181, an attacker must first obtain the ability to execute high-privileged code on the target guest system.
Are there any known fixes for CVE-2021-20181?
Yes, fixes for CVE-2021-20181 are available. Please refer to the relevant vendor or distribution for the specific fixes.
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