CVE-2026-55426 json
linuxfabrik-lib: Local privilege escalation using embedded command
published 2026-07-06 4 mo ago modified 2026-09-09 1 mo ago also GHSA-798h-hpph-m24j , PYSEC-2026-2594 , EUVD-2026-61493
- cvss
- 7.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 11%
- public exploits
- 0
- none known
Summary
linuxfabrik-lib provides Python modules for database access, caching, shell execution, and API integrations, and Linuxfabrik Monitoring Plugins uses those modules to run external monitoring commands. From the earliest affected releases until linuxfabrik-lib 5.0.0 and Linuxfabrik Monitoring Plugins 6.0.0, check plugins embedded user-controlled values in command strings passed to lib.shell.shell_exec(), which split strings at pipe characters and executed the resulting commands. In check-plugins/restic-check/restic-check, the --repo parameter could inject a pipe-delimited command into a constructed restic invocation, and sudo-authorized execution allowed a compromised nagios or icinga account to run that command as root. The shared library also accepted command strings and a shell parameter, while numerous plugins constructed external commands from attacker-influenced arguments. The fixes require argv lists, always use shell=False, remove pipe splitting, and reject option-like positional values through lib.shell.safe_cli_value(). These issues are fixed in linuxfabrik-lib 5.0.0 and Linuxfabrik Monitoring Plugins 6.0.0.
Patch / fix
- pypi linuxfabrik-lib 5.0.0
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- total
- Assessed
- 2 mo ago
Exploit prediction
0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| GitHub | 3.1 | 7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| OSV | 3.1 | 7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | linuxfabrik-lib | <5.0.0 |
5.0.0 |
Affected products
- Linuxfabrik monitoring-plugins
- Linuxfabrik lib
Classification
- Weakness
-
- CWE-78 Improper Neutralization of Special Elements used in an OS Command
References
- github.com /Linuxfabrik/monitoring-plugins/commit/23bb570f41fc8d9caf30b30074bba0e3db1b357a
-
github.com
/Linuxfabrik/monitoring-plugins/security/advisories/GHSA-798h-hpph-m24j
web
- github.com /Linuxfabrik/lib/blob/main/CHANGELOG.md
- github.com /Linuxfabrik/lib/releases/tag/v5.0.0
- github.com /Linuxfabrik/monitoring-plugins/blob/main/CHANGELOG.md
- github.com /Linuxfabrik/monitoring-plugins/releases/tag/v6.0.0
-
github.com
/Linuxfabrik/monitoring-plugins
package
-
pypi.org
/project/linuxfabrik-lib
package
-
github.com
/advisories/GHSA-798h-hpph-m24j
advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-55426
advisory
Sources
- CVE List CVE-2026-55426
- GitHub Advisory GHSA-798h-hpph-m24j
- NVD CVE-2026-55426
- OSV PYSEC-2026-2594
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