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Vulnerability · Published Sep 17, 2026 · Assigned by GitHub_M

CVE-2026-54576mport package installation has symlink TOCTOU in chown and chmod handling

Medium 5.8

In plain English

A medium-severity security flaw in mport from MidnightBSD. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 1% of all known vulnerabilities).

Severity (CVSS 4.0)5.8Medium
Exploit odds (30 days)0.1%top 98.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

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.

Affected products (as reported)

VendorProductVersions
MidnightBSD mport < 2.7.8

Weakness: CWE-59, CWE-367 · Vector: CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N

References