GHSA-pmf6-rcx4-v53v
mkfifo: permissions of an existing file are changed after FIFO creation fails
Packages
Details
As written in the advisory (Markdown source, shown as plain text).
When `mkfifo()` fails (e.g. target already exists), the code shows an error but is missing a `continue;`, so it falls through to `fs::set_permissions` and changes the permissions of the pre-existing file to the default FIFO mode (`0o666` & umask -> `0644`).
```
$ touch secret; chmod 000 secret
$ coreutils mkfifo secret fifo3 fifo4
mkfifo: cannot create fifo 'secret': File exists
$ ll secret # uutils:
prw-r--r-- secret # changed to 644 (GNU leaves it 000)
```
**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_
References
External links from the advisory. They lead to third-party sites.