HIGH
CVE-2021-26910
CWE-367Published: February 8, 2021· Updated: Jun 17, 2026
7.0
CVSS v3.1
Official 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.
Technical Analysis
CVE-2021-26910 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 7.0.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorLocal
Attack ComplexityHigh
Privileges Req.Low
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Affected Vendors & Products
Debian1 product(s)
debian linux
firejail_project1 product(s)
firejail
Source: NVD CPE · 3 total CPE entries
Exploit & PoC Resources
NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.
Official Patches & Advisories
All References (16)
→
http://www.openwall.com/lists/oss-security/2021/02/09/1Exploit · Mailing List · Patch · Third Party Advisory
→
https://github.com/netblue30/firejail/commit/97d8a03cad19501f017587cc4e47d8418273834bPatch · Third Party Advisory
→
https://github.com/netblue30/firejail/releases/tag/0.9.64.4Release Notes · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2021/02/msg00015.htmlThird Party Advisory
→
https://security.gentoo.org/glsa/202105-19Third Party Advisory
→
https://unparalleled.eu/blog/2021/20210208-rigged-race-against-firejail-for-local-root/Exploit · Third Party Advisory
→
https://unparalleled.eu/publications/2021/advisory-unpar-2021-0.txtExploit · Third Party Advisory
→
https://www.debian.org/security/2021/dsa-4849Third Party Advisory
→
http://www.openwall.com/lists/oss-security/2021/02/09/1Exploit · Mailing List · Patch · Third Party Advisory
→
https://github.com/netblue30/firejail/commit/97d8a03cad19501f017587cc4e47d8418273834bPatch · Third Party Advisory
→
https://github.com/netblue30/firejail/releases/tag/0.9.64.4Release Notes · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2021/02/msg00015.htmlThird Party Advisory
→
https://security.gentoo.org/glsa/202105-19Third Party Advisory
→
https://unparalleled.eu/blog/2021/20210208-rigged-race-against-firejail-for-local-root/Exploit · Third Party Advisory
→
https://unparalleled.eu/publications/2021/advisory-unpar-2021-0.txtExploit · Third Party Advisory
Quick Facts
CVE IDCVE-2021-26910
CVSS Score7.0 / 10
SeverityHIGH
WeaknessCWE-367
CISA KEVNo
Affected2 vendor(s)
PublishedFeb 8, 2021
Related CVEs (CWE-367)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-26910 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.