CVE-2026-54580 mport index decompression can leave partial or corrupt index data after zstd failures
A malicious mirror can cause package index corruption or denial of service in MidnightBSD's mport by exploiting improper error handling in zstd decompression.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-54580?
CVE-2026-54580 is a high-severity denial of service vulnerability in MidnightBSD mport, published on 17 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Which versions are affected by CVE-2026-54580?
How do I fix CVE-2026-54580?
No fix has been published for CVE-2026-54580 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-54580 being exploited?
There is no known exploitation of CVE-2026-54580 in the wild and no public exploit code.
Sources
Also known as GHSA-ffqj-j42r-747w.