CVE-2026-54576 mport package installation has symlink TOCTOU in chown and chmod handling
A local attacker can exploit a symlink race condition during package installation to modify permissions of arbitrary files, potentially escalating privileges.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-54576?
CVE-2026-54576 is a medium-severity vulnerability in MidnightBSD mport, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
mport is the MidnightBSD Package Manager. Prior to 2.7.8, do_actual_install() in libmport/bundle_read_install_pkg.c used path-based lstat(), chown(), stat(), and chmod() operations while installing package files. A local attacker with write access to a target directory could replace a checked file with a symlink before privileged ownership or mode changes were applied, redirecting those changes to an attacker-selected path and compromising filesystem integrity or permissions. This issue is fixed in version 2.7.8.
Which versions are affected by CVE-2026-54576?
How do I fix CVE-2026-54576?
No fix has been published for CVE-2026-54576 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-54576 being exploited?
There is no known exploitation of CVE-2026-54576 in the wild and no public exploit code.
Sources
Also known as GHSA-23g3-7fv3-3ccf.