What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 5.8 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-17 · updated 2026-09-18
• Weakness: CWE-59

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

• MidnightBSD mport: before 2.7.8

References

• https://github.com/MidnightBSD/mport/commit/4676ac05b1056b54a3d38d03ae8a478bf12c9abe
• https://github.com/MidnightBSD/mport/pull/150
• https://github.com/MidnightBSD/mport/releases/tag/2.7.8
• https://github.com/MidnightBSD/mport/security/advisories/GHSA-23g3-7fv3-3ccf

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