SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityDeferred

CVE-2026-54581

Prior to 2.7.8, the mport_fetch_bootstrap_index() function in libmport/fetch.c could return success when bootstrap index hash verification encountered a missing or invalid hash because the failure path did not preserve a fatal result.

HIGH 8.3EPSS 0.22%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.22%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

mport is the MidnightBSD Package Manager. Prior to 2.7.8, the mport_fetch_bootstrap_index() function in libmport/fetch.c could return success when bootstrap index hash verification encountered a missing or invalid hash because the failure path did not preserve a fatal result. A network attacker or compromised mirror able to alter bootstrap index content or its transport path could therefore cause mport to proceed with an unverified or tampered bootstrap package index. This issue is fixed in version 2.7.8.

CVSS 4.0
8.3 HIGHCVSS: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/M
EPSS
0.22% probability · 12th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-345, CWE-347
Source
security-advisories@github.com
EPSS trend
0%3%5%27 October 2026: 0.22%27 October 202627 October 2026

EPSS 0.2% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.