CVE-2026-47251

MEDIUM

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

Title source: cna
STIX 2.1

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.

References (2)

Core 2
Core References
X_Refsource_Misc x_refsource_misc
https://github.com/strukturag/libheif/issues/1712

Scores

CVSS v3 6.1
EPSS 0.0018
EPSS Percentile 7.8%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact partial

Details

CWE
CWE-125 CWE-190
Status published
Products (2)
struktur/libheif < 1.22.0
strukturag/libheif < 1.22.0
Published Jul 21, 2026
Tracked Since Jul 22, 2026