Interpretation Conflict in libheif - #VU158756
Published: November 3, 2026
Vulnerability identifier: #VU158756
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-436
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service through excessive memory allocation.
The vulnerability exists due to inconsistent interpretation of AV1 UVLC codes and ignored parsing failures in libheif's AV1 coded-size scanner when processing crafted AVIF files. A remote attacker can supply a file with a long UVLC code that causes the scanner to skip the sequence header or read a small decoy size, bypassing the coded-size check and causing excessive memory allocation when the libaom backend decodes the actual large frame.
Affected software
libheif
Remediation
Install security update from vendor's website.
libheif - update to 1.23.7