mport package fetch and clean paths are vulnerable to TOCTOU filesystem races

published 2026-09-17 52 d ago modified 2026-09-21 48 d ago also EUVD-2026-82327

cvss: 5.8; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.1%; EPSS 0.1% chance of exploitation in 30 days, percentile 1%
public exploits: 0; none known

mport is the MidnightBSD Package Manager. Prior to 2.7.8, privileged package fetch and cache-cleaning operations used race-prone path handling across libmport/fetch.c, libmport/clean.c, libmport/util.c, libmport/bundle_read_install_pkg.c, libmport/delete_primative.c, and libexec/mport.create/mport.create.c. A local attacker with write access to a participating package cache or staging path could race path checks and replacement operations to redirect package downloads, cleanup, or install-related side effects outside the intended cache. The affected lifecycle helper paths also used shell-form invocation, increasing command-line interpretation risk during privileged helper execution. This issue is fixed in version 2.7.8.

Patch / fix

links 3

github.com/MidnightBSD/mport@29154b0 commit
github.com/MidnightBSD/mport#118 pull request
github.com/MidnightBSD/mport/releases/tag/2.7.8 release

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 48 d ago (2026-09-21)

Exploit prediction

0.12% chance of exploitation in the next 30 days, higher than 1% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	5.8	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
CNA	4.0	5.8	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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

MidnightBSD mport

Classification

Weakness

CWE-78 Improper Neutralization of Special Elements used in an OS Command
CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition

References

Sources

CVE List CVE-2026-54575
NVD CVE-2026-54575

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary