Out-of-bounds Read The advisory has been revoked - it doesn't affect any version of package libheif (opens in a new tab)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-DEBIAN14-LIBHEIF-17782242
- published2 Jul 2026
- disclosed21 Jul 2026
Introduced: 2 Jul 2026
CVE-2026-47251 (opens in a new tab)Amendment
The Debian security team deemed this advisory irrelevant for Debian:14.
NVD Description
Note: Versions mentioned in the description apply only to the upstream libheif package and not the libheif package as distributed by Debian.
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.