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.
CVE-2021-26910
This high-severity CVE scores 7.8 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 64% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 7.8
- EG Score
- 7.8(medium)
- EG Risk
- 40(Track)EG Risk 40/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity78% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 38%
- KEV
- Not listed
Published
February 8, 2021
Last Modified
November 21, 2024
References (16)
- cve@mitrehttp://www.openwall.com/lists/oss-security/2021/02/09/1
- cve@mitrehttps://github.com/netblue30/firejail/commit/97d8a03cad19501f017587cc4e47d8418273834b
- cve@mitrehttps://github.com/netblue30/firejail/releases/tag/0.9.64.4
- cve@mitrehttps://lists.debian.org/debian-lts-announce/2021/02/msg00015.html
- cve@mitrehttps://security.gentoo.org/glsa/202105-19
- cve@mitrehttps://unparalleled.eu/blog/2021/20210208-rigged-race-against-firejail-for-local-root/
- cve@mitrehttps://unparalleled.eu/publications/2021/advisory-unpar-2021-0.txt
- cve@mitrehttps://www.debian.org/security/2021/dsa-4849
- af854a3a-2127-422b-91ae-364da2661108http://www.openwall.com/lists/oss-security/2021/02/09/1
- af854a3a-2127-422b-91ae-364da2661108https://github.com/netblue30/firejail/commit/97d8a03cad19501f017587cc4e47d8418273834b
- af854a3a-2127-422b-91ae-364da2661108https://github.com/netblue30/firejail/releases/tag/0.9.64.4
- af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2021/02/msg00015.html
- af854a3a-2127-422b-91ae-364da2661108https://security.gentoo.org/glsa/202105-19
- af854a3a-2127-422b-91ae-364da2661108https://unparalleled.eu/blog/2021/20210208-rigged-race-against-firejail-for-local-root/
- af854a3a-2127-422b-91ae-364da2661108https://unparalleled.eu/publications/2021/advisory-unpar-2021-0.txt
Patch Availability(1)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | firejail-profiles (0.9.62-3ubuntu0.1) @ focal | 2026-05-26 | ubuntu |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(5 across 5 ecosystems)
Debian:10(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| firejail | 0.9.58.2-2, 0.9.58.2-2+deb10u1 | 0.9.58.2-2+deb10u2 | — |
Debian:11(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| firejail | — | 0.9.64.4-1 | — |
Debian:12(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| firejail | — | 0.9.64.4-1 | — |
Debian:13(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| firejail | — | 0.9.64.4-1 | — |
Debian:9(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| firejail | 0.9.44.8-2, 0.9.44.8-2+deb9u1 | 0.9.44.8-2+deb9u2 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
All Vendor Advisories
(1)
Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.
Data Freshness Timeline
(refreshed 8× in last 7d / 31× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
Showing the most recent 100 of 165 total refreshes for this CVE.
- 2026-09-18 19:23 UTCEPSS rescore
- 2026-09-17 19:23 UTCEPSS rescore
- 2026-09-17 19:23 UTCEPSS rescore
- 2026-09-16 14:05 UTCEPSS rescore
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- 2026-09-13 16:43 UTCEPSS rescore
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- 2026-09-11 09:33 UTCEPSS rescore
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- 2026-09-06 23:01 UTCOSV refresh
- 2026-09-06 13:44 UTCEPSS rescore
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- 2026-08-30 19:14 UTCEPSS rescore
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- 2026-08-28 21:37 UTCEPSS rescore
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- 2026-08-26 14:42 UTCEPSS rescore
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- 2026-08-21 23:46 UTCEPSS rescore
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- 2026-08-20 09:01 UTCOSV refresh
- 2026-08-19 17:01 UTCEPSS rescore
- 2026-08-18 13:45 UTCEPSS rescore
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- 2026-08-08 16:33 UTCEPSS rescore
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- 2026-08-06 13:43 UTCEPSS rescore
- 2026-08-05 19:14 UTCEPSS rescore
- 2026-08-05 04:40 UTCOSV refresh
- 2026-08-04 15:06 UTCEPSS rescore
- 2026-08-04 10:34 UTCEPSS rescore
- 2026-08-03 10:33 UTCEPSS rescore
- 2026-08-02 02:24 UTCEPSS rescore
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- 2026-07-30 16:25 UTCEPSS rescore
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- 2026-07-28 15:33 UTCEPSS rescore
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- 2026-07-23 14:16 UTCEPSS rescore
- 2026-07-23 01:59 UTCEG score recompute
- 2026-07-22 22:45 UTCEG score recompute▲ 0.80
- 2026-07-22 14:06 UTCEPSS rescore
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- 2026-07-21 15:22 UTCEPSS rescore
- 2026-07-21 15:22 UTCEPSS rescore
- 2026-07-20 17:05 UTCEPSS rescore
- 2026-07-19 14:28 UTCEPSS rescore
- 2026-07-19 02:52 UTCOSV refresh
- 2026-07-19 02:27 UTCEPSS rescore
- 2026-07-19 02:27 UTCEPSS rescore
- 2026-07-18 10:02 UTCEPSS rescore
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- 2026-07-16 17:00 UTCEPSS rescore
- 2026-07-15 16:55 UTCEPSS rescore
- 2026-07-15 16:55 UTCEPSS rescore
- 2026-07-15 01:58 UTCEPSS rescore
- 2026-07-13 22:27 UTCEPSS rescore
- 2026-07-13 22:27 UTCEPSS rescore
- 2026-07-13 06:10 UTCEPSS rescore
- 2026-07-12 05:44 UTCEPSS rescore
- 2026-07-12 05:44 UTCEPSS rescore
- 2026-07-11 08:25 UTCEPSS rescore
- 2026-07-11 08:25 UTCEPSS rescore
- 2026-07-09 19:07 UTCEPSS rescore
- 2026-07-08 15:12 UTCEPSS rescore
- 2026-07-07 13:43 UTCEPSS rescore
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- 2026-07-02 16:57 UTCEPSS rescore
- 2026-07-01 15:03 UTCEPSS rescore
- 2026-07-01 09:18 UTCOSV refresh
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Frequently asked(5)
What is CVE-2021-26910?
When was CVE-2021-26910 disclosed?
Is CVE-2021-26910 actively exploited?
What is the CVSS score of CVE-2021-26910?
How do I remediate CVE-2021-26910?
Dependency Blast Radius
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