linuxfabrik-lib: Arbitrary root file read via live --test argument (lib.lftest) across sudoers-whitelisted plugins (LPE)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.5 · CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS

• CVE-2026-73974: 0.17% estimated exploitation activity in the next 30 days; percentile 6.19 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Every Linuxfabrik check plugin that supports the shared --test argument (routed through lib.lftest.test()) will, when --test is supplied, treat the first CSV element as a filesystem path and read its full contents as the plugin's simulated STDOUT — running as root when the plugin is invoked through the shipped nagios/icinga sudoers allowlist. --test is a live production argument (centrally mapped to argparse.SUPPRESS, so it is hidden from --help but still accepted on the command line), not a build-time-only gate. This yields an arbitrary root file-read primitive (full disclosure on deb-updates; filtered disclosure / existence-and-readability oracle on ~22 other whitelisted plugins), i.e. local privilege escalation from the nagios account to root. Root Cause - lib.lftest.test(args) (lftest.py lines 659-664): stdout = args[0]; if stdout and os.path.isfile(stdout): , stdout = disk.readfile(stdout). Element[1] (stderr channel) is read the same way. There is no path confinement on…

Published by the source

18 Aug 2026, 21:18 UTC

Last modified by the source

18 Aug 2026, 21:19 UTC

Source last checked

26 Oct 2026, 13:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-rh9c-rqvg-f7pr

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# Patch Next advisory brief: CVE-2026-73974

Advisory: linuxfabrik-lib: Arbitrary root file read via live --test argument (lib.lftest) across sudoers-whitelisted plugins (LPE)
IDs: CVE-2026-73974, GHSA-rh9c-rqvg-f7pr
Record: https://patchnext.com/advisories/cve-2026-73974 (revision 1, source checked 26 Oct 2026, 13:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: linuxfabrik-lib 6.1.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI linuxfabrik-lib: affected < 6.1.0; fixed in 6.1.0

## Suggested inspection (read-only)
- `python -m pip show linuxfabrik-lib`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on linuxfabrik-lib.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-rh9c-rqvg-f7pr (GitHub-reviewed advisory GHSA-rh9c-rqvg-f7pr lists affected ranges: PyPI linuxfabrik-lib >=0 <6.1.0)

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