UBUNTU-CVE-2021-3493
The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges.
02 / AFFECTED SOFTWARE
Affected packages
93 explicit affected versions
50 explicit affected versions
6 explicit affected versions
6 explicit affected versions
62 explicit affected versions
24 explicit affected versions
43 explicit affected versions
16 explicit affected versions
73 explicit affected versions
23 explicit affected versions
1 explicit affected versions
1 explicit affected versions
16 explicit affected versions
1 explicit affected versions
7 explicit affected versions
12 explicit affected versions
1 explicit affected versions
26 explicit affected versions
34 explicit affected versions
61 explicit affected versions
25 explicit affected versions
18 explicit affected versions
10 explicit affected versions
41 explicit affected versions
11 explicit affected versions
60 explicit affected versions
40 explicit affected versions
1 explicit affected versions
8 explicit affected versions
1 explicit affected versions
26 explicit affected versions
13 explicit affected versions
17 explicit affected versions
57 explicit affected versions
1 explicit affected versions
28 explicit affected versions
33 explicit affected versions
10 explicit affected versions
11 explicit affected versions
95 explicit affected versions
26 explicit affected versions
2 explicit affected versions
60 explicit affected versions
22 explicit affected versions
65 explicit affected versions
1 explicit affected versions
126 explicit affected versions
6 explicit affected versions
19 explicit affected versions
73 explicit affected versions
1 explicit affected versions
22 explicit affected versions
16 explicit affected versions
1 explicit affected versions
16 explicit affected versions
1 explicit affected versions
19 explicit affected versions
6 explicit affected versions
82 explicit affected versions
15 explicit affected versions
42 explicit affected versions
44 explicit affected versions
16 explicit affected versions
11 explicit affected versions
16 explicit affected versions
38 explicit affected versions
9 explicit affected versions
104 explicit affected versions
16 explicit affected versions
88 explicit affected versions
39 explicit affected versions
50 explicit affected versions
10 explicit affected versions
15 explicit affected versions
39 explicit affected versions
1 explicit affected versions
12 explicit affected versions
19 explicit affected versions
4 explicit affected versions
6 explicit affected versions
1 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges.
05 / REFERENCES
Further evidence
- https://ubuntu.com/security/CVE-2021-3493
- https://ubuntu.com/security/notices/USN-4915-1
- https://ubuntu.com/security/notices/USN-4916-1
- https://ubuntu.com/security/notices/USN-4917-1
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog
- https://www.cve.org/CVERecord?id=CVE-2021-3493
- https://www.openwall.com/lists/oss-security/2021/04/16/1