CVE-2021-26910
Firejail before 0.9.64.4 allows attackers to bypass intended access restrictions because there is a TOCTOU race condition between a stat operation and an OverlayFS mount operation.
02 Description
Firejail before 0.9.64.4 allows attackers to bypass intended access restrictions because there is a TOCTOU race condition between a stat operation and an OverlayFS mount operation.
03 Exploitation and scoring
- Exploitation
- Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
- SSVC decision
- Not assessed by CISA
- EPSS probability
- 0.44% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 38.3% of scored records. A rank, not a probability.
- NVD base score
- 7.0 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- NVD analysis status
- Modified. NVD last modified this record on 2026-06-17.
- Red Hat severity
- No Red Hat rating. Red Hat rates the CVEs that affect its products.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2021-02-08 19:56Z5 YR AGO
- Last updated
- 2024-08-03 20:33Z2 YR AGO
- Reserved
- 2021-02-08
- Assigning CNA
- mitre
- Record state
- PUBLISHED
- Severity
- High (CVSS 7.8)
- CNA CVSS vector
- CVSS:3.1/AC:L/AV:L/A:H/C:H/I:H/PR:L/S:U/UI:N
- Weaknesses
- CWE-367Time-of-check Time-of-use (TOCTOU) Race ConditionBase
- Data version
- 5.1
- Document digest
- b58b4c0e598cd3a0708cdc8d6b4c508c59098a22cd602b8088451192844fca6e
05 Affected products
06 References
- github.comhttps://github.com/netblue30/firejail/commit/97d8a03cad19501f017587cc4e47d8418273834b
- unparalleled.euhttps://unparalleled.eu/publications/2021/advisory-unpar-2021-0.txt
- unparalleled.euhttps://unparalleled.eu/blog/2021/20210208-rigged-race-against-firejail-for-local-root/
- github.comhttps://github.com/netblue30/firejail/releases/tag/0.9.64.4
- www.openwall.com[oss-security] 20210209 Re: [cve-pending] Firejail: root privilege escalation in OverlayFS codehttp://www.openwall.com/lists/oss-security/2021/02/09/1
- www.debian.orgDSA-4849https://www.debian.org/security/2021/dsa-4849
- lists.debian.org[debian-lts-announce] 20210211 [SECURITY] [DLA 2554-1] firejail security updatehttps://lists.debian.org/debian-lts-announce/2021/02/msg00015.html
- security.gentoo.orgGLSA-202105-19https://security.gentoo.org/glsa/202105-19
07 Fixed in
Arch Linux
- firejail Fixed in 0.9.64.4-1
Source: Arch Linux Security Tracker, the Arch Linux security team. Reformatted by exploit.cc.
Debian 12
- firejail Fixed in 0.9.64.4-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 13
- firejail Fixed in 0.9.64.4-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 16.04 LTS
- firejail No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 18.04 LTS
- firejail No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 20.04 LTS
- firejail Fixed in 0.9.62-3ubuntu0.1
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.