CVE-2026-47251

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.

• CWE-125
• CWE-190

• https://github.com/strukturag/libheif/issues/1712Issue Tracking
• https://github.com/strukturag/libheif/security/advisories/GHSA-p6q9-fhf2-vj9vExploit, Vendor Advisory
• https://github.com/strukturag/libheif/issues/1712Issue Tracking
• https://github.com/strukturag/libheif/security/advisories/GHSA-p6q9-fhf2-vj9vExploit, Vendor Advisory

Published

Jul 21, 2026

Last Modified

Jul 27, 2026

Status

Analyzed

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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