CVE-2021-40084 json
opensysusers through 0.6 does not safely use eval on files in sysusers.d that may contain shell metacharacters.
published 2021-08-25 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-27274
- cvss
- 9.8
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 2.9%
- EPSS 2.9% chance of exploitation in 30 days, percentile 87%
- public exploits
- 0
- none known
Summary
opensysusers through 0.6 does not safely use eval on files in sysusers.d that may contain shell metacharacters. For example, it allows command execution via a crafted GECOS field whereas systemd-sysusers (a program with the same specification) does not do that.
Patch / fix
- opensysusers Debian 14, Debian 13, Debian 12 0.6-3
debian advisories DEBIAN-CVE-2021-40084
Exploit prediction
2.93% chance of exploitation in the next 30 days, higher than 87% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- bugs.debian.org https://bugs.debian.org/992058 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 7.5 | AV:N/AC:L/Au:N/C:P/I:P/A:P |
Classification
- Weakness
-
- CWE-94 Improper Control of Generation of Code
References
-
bugs.debian.org
/992058
exploit, mailing-list, third-party-advisory
-
github.com
/artix-linux/opensysusers/releases
release-notes, third-party-advisory
Sources
- CVE List CVE-2021-40084
- NVD CVE-2021-40084
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.