Vulnerability Details : CVE-2021-4120
Potential exploit
snapd 2.54.2 fails to perform sufficient validation of snap content interface and layout paths, resulting in the ability for snaps to inject arbitrary AppArmor policy rules via malformed content interface and layout declarations and hence escape strict snap confinement. Fixed in snapd versions 2.54.3+18.04, 2.54.3+20.04 and 2.54.3+21.10.1
Vulnerability category: Input validation
Products affected by CVE-2021-4120
- cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
- cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:*
- cpe:2.3:o:canonical:ubuntu_linux:21.10:*:*:*:*:*:*:*
- cpe:2.3:a:canonical:snapd:*:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2021-4120
0.10%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 28 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2021-4120
| Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
|---|---|---|---|---|---|---|
|
4.6
|
MEDIUM | AV:L/AC:L/Au:N/C:P/I:P/A:P |
3.9
|
6.4
|
NIST | |
|
7.8
|
HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
1.8
|
5.9
|
NIST | |
|
8.2
|
HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H |
1.5
|
6.0
|
Canonical Ltd. |
CWE ids for CVE-2021-4120
-
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.Assigned by:
- nvd@nist.gov (Primary)
- security@ubuntu.com (Secondary)
References for CVE-2021-4120
-
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3QTBN7LLZISXIA4KU4UKDR27Q5PXDS2U/
[SECURITY] Fedora 34 Update: snapd-2.54.3-1.fc34 - package-announce - Fedora Mailing-ListsMailing List;Third Party Advisory
-
http://www.openwall.com/lists/oss-security/2022/02/18/2
oss-security - CVE-2021-4120: Insufficient validation of snap content interface and layout pathsExploit;Mailing List;Third Party Advisory
-
https://bugs.launchpad.net/snapd/+bug/1949368
Bug #1949368 “snapd fails to validate content interface settings...” : Bugs : snapdExploit;Issue Tracking;Third Party Advisory
-
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XCGHG6LJAVJJ72TMART6A7N4Z6MSTGI7/
[SECURITY] Fedora 35 Update: snapd-2.54.3-1.fc35 - package-announce - Fedora Mailing-ListsMailing List;Third Party Advisory
-
https://ubuntu.com/security/notices/USN-5292-1
USN-5292-1: snapd vulnerabilities | Ubuntu security notices | UbuntuPatch;Vendor Advisory
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