Quick answers
- Is CVE-2026-54576 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-54576 being exploited in the wild.
- How severe is CVE-2026-54576?
- Informational severity, with a CVSS score of 5.5, published 17 September 2026.
- Which products and versions are affected?
- MidnightBSD Mport before 2.7.8.
- Is there a fix for CVE-2026-54576?
- A patch was published on 2026-05-31: Fix merged in commit 4676ac0; version 2.7.8 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-54576 attacked?
- It is attacked with local access.
- Am I affected by CVE-2026-54576?
- Check whether you run MidnightBSD Mport at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability is a time-of-check-time-of-use (TOCTOU) race condition in do_actual_install() within libmport/bundle_read_install_pkg.c. The installer used path-based lstat(), chown(), stat(), and chmod() operations in sequence when applying ownership and permission metadata to extracted package files. An attacker with write access to a target directory could replace a regular file with a symlink between the lstat() check and the chown()/chmod() calls, causing the privileged operations to follow the symlink and modify an arbitrary file. The fix hardens the code by opening extracted files with O_NOFOLLOW and using descriptor-based fstat(), fchown(), and fchmod() operations instead, preventing symlink traversal and closing the race window. Version 2.7.8 and later include this fix.
Affected products
- MidnightBSD mport before 2.7.8
Timeline
- 2026-05-31: disclosed
- 2026-05-31: patched: Fix merged in commit 4676ac0; version 2.7.8 released
- 2026-09-17: advisory