CVE-2026-47251

Publication date 21 July 2026

Last updated 7 August 2026

Ubuntu priority

Cvss 3 Severity Score

Description

libheif is a HEIF and AVIF file format decoder and encoder. The fix for CVE-2026-3949 (commit `b97c8b5`, PR #1712) introduced an integer overflow in the very security check it added. The check itself can be bypassed, allowing a crafted HEIF file with a VVC track to trigger the same out-of-bounds heap read that CVE-2026-3949 was meant to prevent. This is a separate, currently-unpatched vulnerability. Issue #1712 was closed as fixed without testing the edge case where `size` is near `UINT32_MAX`. Version 1.22.0 patches the issue.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
libheif	26.04 LTS resolute	Not affected
	25.10 questing	Not affected
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not affected

Notes

kkernick

This vulnerability was introduced by the fix for CVE-2026-3949 Which does not affect Ubuntu packages.

Severity score breakdown

CVSS version:

Base score 6.8 · Medium

Base metrics

Parameter	Value
Attack vector	Local
Attack complexity	Low
Attack requirements	None
Privileges required	None
User interaction	Active
Vulnerable system - Confidentiality impact	Low
Vulnerable system - Integrity impact	None
Vulnerable system - Availability impact	High
Subsequent system - Confidentiality impact	None
Subsequent system - Integrity impact	None
Subsequent system - Availability impact	None

Scores

Parameter	Value
Base score	6.8 · Medium
Base + Threat score	-
Base + Environmental score	-
Base + Threat + Environmental score	-

Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N

Base score 6.1 · Medium