mport package bundle downloads allow unsafe destination filenames

published 2026-09-17 52 d ago modified 2026-09-17 52 d ago also EUVD-2026-82319

cvss: 8.3; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits: 0; none known

mport is the MidnightBSD Package Manager. Prior to 2.7.8, libmport/fetch.c did not consistently reject empty, dot, dot-dot, or slash-containing bundle filenames before composing package download and write paths. Malicious package index data could place an unsafe value in indexEntry->bundlefile, and the missing is_valid_bundle_filename() checks allowed downloaded package data to be written outside the intended cache location or to an unsafe destination name. This issue is fixed in version 2.7.8.

Patch / fix

links 3

github.com/MidnightBSD/mport@cad959d commit
github.com/MidnightBSD/mport#125 pull request
github.com/MidnightBSD/mport/releases/tag/2.7.8 release

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 52 d ago (2026-09-17)

Exploit prediction

0.54% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.3	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N
CNA	4.0	8.3	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/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-22 Improper Limitation of a Pathname to a Restricted Directory
CWE-73 External Control of File Name or Path

References

Sources

CVE List CVE-2026-54583
NVD CVE-2026-54583

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