VDB
CVE-2021-3493
CVE-2021-3493
PUBLISHED
KEV
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.
EPSS 79.71% · 99.1th percentile
Risk Scores
EPSS Score
79.71%
99.1th percentile
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Ubuntu:18.04:LTS | linux-gcp-5.4 | 5.4.0-1024.24~18.04.1, 5.4.0-1028.29~18.04.1, 5.4.0-1025.25~18.04.1 |
| Ubuntu:16.04:LTS | linux-raspi2 | 4.4.0-1141.151, 4.4.0-1136.145, 4.4.0-1137.146 |
| Ubuntu:20.04:LTS | linux-riscv-5.8 | *, *, 5.8.0-20.22~20.04.1 |
| Ubuntu:20.04:LTS | linux-azure | 5.3.0-1003.3, 0, 5.4.0-1040.42 |
| Ubuntu:20.04:LTS | linux-gcp | 5.4.0-1032.34, 5.4.0-1036.39, 5.4.0-1037.40 |
| Ubuntu:20.04:LTS | linux-raspi2 | 5.3.0-1007.8, 5.3.0-1014.16, 0 |
| Ubuntu:16.04:LTS | linux-aws-hwe | 4.15.0-1045.47~16.04.1, 4.15.0-1044.46~16.04.1, 4.15.0-1043.45~16.04.1 |
| Ubuntu:Pro:FIPS-updates:20.04:LTS | linux-aws-fips | 0, * |
| Ubuntu:Pro:FIPS-updates:20.04:LTS | linux-azure-fips | 5.4.0-1022.22+fips1, 0 |
| Ubuntu:16.04:LTS | linux-azure | 4.15.0-1057.62, *, 4.15.0-1055.60 |
| Ubuntu:18.04:LTS | linux-hwe | 5.0.0-23.24~18.04.1, 5.0.0-25.26~18.04.1, * |
| Ubuntu:18.04:LTS | linux-raspi2 | 4.15.0-1034.36, 4.15.0-1032.34, 4.15.0-1054.58 |
| Ubuntu:18.04:LTS | linux-aws-5.0 | 5.0.0-1025.28, 0, * |
| Ubuntu:18.04:LTS | linux-aws | 4.15.0-1058.60, 0, 4.15.0-1001.1 |
| Ubuntu:Pro:FIPS-updates:18.04:LTS | linux-azure-fips | 4.15.0-2006.7, 4.15.0-2024.27, 0 |
| Ubuntu:Pro:FIPS:18.04:LTS | linux-aws-fips | 0, 4.15.0-2000.4 |
| Ubuntu:18.04:LTS | linux-gke-5.3 | 0, 5.3.0-1011.12~18.04.1, 5.3.0-1012.13~18.04.1 |
| Ubuntu:18.04:LTS | linux-snapdragon | 4.15.0-1069.76, 4.15.0-1067.74, 4.15.0-1066.73 |
| Ubuntu:18.04:LTS | linux-azure-5.4 | 5.4.0-1031.32~18.04.1, 0, * |
| Ubuntu:18.04:LTS | linux-gke-5.4 | 5.4.0-1035.37~18.04.1, 5.4.0-1039.41~18.04.1, * |
…and 59 more
Timeline
- Jan 16, 1970 VulnCheck XDB Entry
- Jan 16, 1970 VulnCheck XDB Entry
- Jan 17, 1970 VulnCheck XDB Entry
- Jan 19, 1970 VulnCheck XDB Entry
- Jan 19, 1970 VulnCheck XDB Entry
- Jan 19, 1970 VulnCheck XDB Entry
- Jan 19, 1970 VulnCheck XDB Entry
- Jan 19, 1970 VulnCheck XDB Entry
- Jan 19, 1970 VulnCheck XDB Entry
- Jan 19, 1970 VulnCheck XDB Entry
- Jan 19, 1970 VulnCheck XDB Entry
- Jan 19, 1970 VulnCheck XDB Entry
References
- https://ubuntu.com/security/CVE-2021-3493 third-party-advisory
- https://ubuntu.com/security/notices/USN-4915-1 vendor-advisory
- https://ubuntu.com/security/notices/USN-4916-1 vendor-advisory
- https://ubuntu.com/security/notices/USN-4917-1 vendor-advisory
- https://www.openwall.com/lists/oss-security/2021/04/16/1 third-party-advisory
- https://www.cve.org/CVERecord?id=CVE-2021-3493 third-party-advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog third-party-advisory