Ubuntu linux kernel
At a glance
- Source
- NVD
- EPSS
- EPSS 49.17 % · percentile 99 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- canonical
- NVD status
- Analyzed
Description
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.
Weaknesses (CWE)
References
- https://ubuntu.com/security/notices/USN-4917-1
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52
- https://www.openwall.com/lists/oss-security/2021/04/16/1
- http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html
- http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html
- http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-3493
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 8.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H | canonical |
| CVSS 3.1 | HIGH 8.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H | NVD · security@ubuntu.com (Secondary) |
| CVSS 3.1 | HIGH 7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | NVD · nvd@nist.gov (Primary) |
| CVSS 2.0 | HIGH 7.2 | AV:L/AC:L/Au:N/C:C/I:C/A:C | NVD · nvd@nist.gov (Primary) |
European references
- ENISA EUVD · EUVD-2021-26815
- GCVE · GCVE-0-2021-3493
CERT-FR advisories
- CERTFR-2021-AVI-372 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2021-AVI-277 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:lts:*:*:*< 18.04cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:lts:*:*:*≥ 18.04.1 < 20.04cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:-:*:*:*< 20.10
Affected products
| Product | Versions |
|---|---|
| Ubuntu · linux kernel | affected 5.8 kernel < 5.8.0-50.56 ; affected 5.4 kernel < 5.4.0-72.80 ; affected 4.15 kernel < 4.15.0-142.146 ; affected 4.4 kernel < 4.4.0-209.241 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| CISA Known Exploited Vulnerabilities | CC0 1.0 |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |