CVE-2026-47251 MEDIUM

CVE-2026-47251: libheif has an incomplete fix for CVE-2026-3949: integer overflow bypass in vvdec_push_data2

Vendor Strukturag
Product libheif
Weakness CWE-125
Published July 21, 2026
Last update July 22, 2026
View on NVD All CVEs

CVSS base score

6.8/10
Attack vector Local
Attack complexity Low
Privileges required None
User interaction —
Confidentiality —
Integrity —

CVSS 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

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

July 21, 2026 CVE published
July 22, 2026 Record updated