mkfifo: permissions of an existing file are changed after FIFO creation fails

Exploitation

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

CVSS

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

EPSS

• CVE-2026-35341: 0.17% estimated exploitation activity in the next 30 days; percentile 5.79 (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.

When mkfifo() fails (e.g. target already exists), the code shows an error but is missing a continue;, so it falls through to fs::setpermissions and changes the permissions of the pre-existing file to the default FIFO mode (0o666 & umask - 0644). Impact: an attacker (or user error) can relax permissions on sensitive owner-only files such as SSH private keys, exposing them to other users. Recommendation: add continue; after the error. Remediation: Acknowledged by Canonical; fixed in PR #10376. --- Reported by Zellic in the uutils coreutils Program Security Assessment (prepared for Canonical, Jan 20 2026), audited commit 3a07ffc5a9bd4c283e75afa548ba1f1957bad242. Finding 3.8. Credit: Zellic. Upstream tracking issue: https://github.com/uutils/coreutils/issues/10020 · CVE-2026-35341

Published by the source

6 Jul 2026, 21:53 UTC

Last modified by the source

6 Jul 2026, 21:53 UTC

Source last checked

26 Oct 2026, 15:43 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-pmf6-rcx4-v53v

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# Patch Next advisory brief: CVE-2026-35341

Advisory: mkfifo: permissions of an existing file are changed after FIFO creation fails
IDs: CVE-2026-35341, GHSA-pmf6-rcx4-v53v
Record: https://patchnext.com/advisories/cve-2026-35341 (revision 1, source checked 26 Oct 2026, 15:43 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: uu_mkfifo 0.6.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io uu_mkfifo: affected < 0.6.0; fixed in 0.6.0

## Suggested inspection (read-only)
- crates.io uu_mkfifo: check the installed version with your package manager.

## 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 uu_mkfifo.
- 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-pmf6-rcx4-v53v (GitHub-reviewed advisory GHSA-pmf6-rcx4-v53v lists affected ranges: crates.io uu_mkfifo >=0 <0.6.0)

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