Vulnerability · Published Sep 17, 2026 · Assigned by GitHub_M

CVE-2026-54580mport index decompression can leave partial or corrupt index data after zstd failures

High 8.3

In plain English

A high-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 0.3% (higher than 18% of all known vulnerabilities).

Severity (CVSS 4.0)8.3High

Exploit odds (30 days)0.3%top 82.0% 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, libmport/util.c did not make every truncated, corrupt, or failed zstd stream fatal in mport_decompress_zstd(), and libmport/fetch.c did not consistently propagate those failures to index-fetch callers. A malicious or faulty mirror could supply compressed package index data that caused ZSTD_decompressStream() or an output write to fail while leaving partial index output available for later use, resulting in package-index integrity loss or denial of service. This issue is fixed in version 2.7.8.

Affected products (as reported)

Vendor	Product	Versions
MidnightBSD	mport	< 2.7.8

Weakness: CWE-354, CWE-755 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N

References

https://github.com/MidnightBSD/mport/security/advisories/GHSA-ffqj-j42r-747w x_refsource_CONFIRM
https://github.com/MidnightBSD/mport/pull/135 x_refsource_MISC
https://github.com/MidnightBSD/mport/commit/b3e11ba078351402082a881209ee6fda5d332e3d x_refsource_MISC
https://github.com/MidnightBSD/mport/releases/tag/2.7.8 x_refsource_MISC