CVE-2026-47251

mediumCVSS 6.1covered by 1 sourcefirst seen 2026-07-21

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.

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Exploitation outlook

Low exploitation risk0.18% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 8% of all EPSS-scored CVEs.

Advisory coverage (1)

mediumCVE-2026-47251: libheif is a HEIF and AVIF file format decoder and encoder. The fix for CVE-2026-3949 (commit …nvd · 2026-07-21

External references

NVD record for CVE-2026-47251

CVE.org record

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