CVE-2026-47251
Medium
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.
SeverityMedium
CVSS6.1
Exploit probability—
ProductStruktur Libheif
PublishedJul 21, 2026
First seenJul 21, 2026
Weakness typeCWE-125Out-of-bounds readCWE-190Integer overflow
How to fix
Update
- struktur libheif1.22.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| struktur libheif | v < 1.22.0 | 1.22.0 |
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