CVE-2021-44731: snapd could be made to escalate privileges and run programs as administrator
First published: Thu Feb 17 2022(Updated: )
A race condition existed in the snapd 2.54.2 snap-confine binary when preparing a private mount namespace for a snap. This could allow a local attacker to gain root privileges by bind-mounting their own contents inside the snap's private mount namespace and causing snap-confine to execute arbitrary code and hence gain privilege escalation. Fixed in snapd versions 2.54.3+18.04, 2.54.3+20.04 and 2.54.3+21.10.1
Credit: security@ubuntu.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| debian/snapd | 2.49-1+deb11u2 2.57.6-1 2.67-1 | |
| Snapcraft Snapd | <=2.54.2 | |
| Ubuntu | =18.04 | |
| Ubuntu | =20.04 | |
| Ubuntu | =21.10 | |
| Red Hat Fedora | =34 | |
| Red Hat Fedora | =35 | |
| Debian Linux | =10.0 | |
| Debian Linux | =11.0 |
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Reference Links
- http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html
- http://seclists.org/fulldisclosure/2022/Dec/4
- http://www.openwall.com/lists/oss-security/2022/02/18/2
- http://www.openwall.com/lists/oss-security/2022/02/23/1
- http://www.openwall.com/lists/oss-security/2022/02/23/2
- http://www.openwall.com/lists/oss-security/2022/11/30/2
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3QTBN7LLZISXIA4KU4UKDR27Q5PXDS2U/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XCGHG6LJAVJJ72TMART6A7N4Z6MSTGI7/
- https://ubuntu.com/security/notices/USN-5292-1
- https://www.debian.org/security/2022/dsa-5080
- https://launchpad.net/bugs/cve/CVE-2021-44731
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3QTBN7LLZISXIA4KU4UKDR27Q5PXDS2U/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XCGHG6LJAVJJ72TMART6A7N4Z6MSTGI7/
- https://www.openwall.com/lists/oss-security/2022/02/17/2
- https://security-tracker.debian.org/tracker/CVE-2021-44731
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-44731
- https://nvd.nist.gov/vuln/detail/CVE-2021-44731
- https://ubuntu.com/security/CVE-2021-44731
Frequently Asked Questions
What is CVE-2021-44731?
CVE-2021-44731 is a vulnerability that existed in the snapd 2.54.2 snap-confine binary when preparing a private mount namespace for a snap, allowing a local attacker to gain root privileges.
How severe is CVE-2021-44731?
CVE-2021-44731 has a severity score of 7.8 (high).
Which software versions are affected by CVE-2021-44731?
The affected software versions include snapd 2.37.4-1+deb10u1, 2.37.4-1+deb10u3, 2.49-1+deb11u2, 2.57.6-1, and 2.60.2-1 on Debian, as well as snapd 2.54.3+18.04 on Ubuntu 18.04 LTS, snapd 2.54.3+20.04 on Ubuntu 20.04 LTS, snapd 2.54.3+21.10.1 on Ubuntu 21.10, and snapd 2.54.3 (upstream version) on Ubuntu (all versions).
How can I fix CVE-2021-44731?
To fix CVE-2021-44731, update snapd to version 2.54.3+18.04 on Ubuntu 18.04 LTS, 2.54.3+20.04 on Ubuntu 20.04 LTS, 2.54.3+21.10.1 on Ubuntu 21.10, or 2.54.3 (upstream version) on Ubuntu (all versions). For Debian, update to snapd versions 2.37.4-1+deb10u1, 2.37.4-1+deb10u3, 2.49-1+deb11u2, 2.57.6-1, or 2.60.2-1.
Where can I find more information about CVE-2021-44731?
You can find more information about CVE-2021-44731 at the following references: [1] http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html [2] http://seclists.org/fulldisclosure/2022/Dec/4 [3] http://www.openwall.com/lists/oss-security/2022/02/18/2
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