CVE-2026-47251: CWE-125: Out-of-bounds Read in strukturag libheif
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.
AI Analysis
Technical Summary
The vulnerability CVE-2026-47251 in strukturag libheif stems from an integer overflow in a security check added to fix CVE-2026-3949. This overflow allows bypassing the check, enabling a specially crafted HEIF file with a VVC track to trigger an out-of-bounds heap read. The issue was not detected during the original fix due to lack of testing edge cases where the size parameter approaches UINT32_MAX. Version 1.22.0 of libheif includes a patch for this vulnerability.
Potential Impact
Successful exploitation can cause an out-of-bounds heap read, potentially leading to information disclosure or application instability. The CVSS 4.0 score is 6.8 (medium severity), reflecting local attack vector with low complexity, no privileges required, user interaction needed, and high impact on availability.
Mitigation Recommendations
Version 1.22.0 of libheif patches this vulnerability. Users and maintainers should upgrade to libheif 1.22.0 or later to remediate this issue. No other official remediation or temporary fixes are documented. Patch status is confirmed by the vendor's versioning information.
CVE-2026-47251: CWE-125: Out-of-bounds Read in strukturag libheif
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.
CVSS v4.0
Score 6.8medium
Affected software
pkg:github/strukturag/libheifRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability CVE-2026-47251 in strukturag libheif stems from an integer overflow in a security check added to fix CVE-2026-3949. This overflow allows bypassing the check, enabling a specially crafted HEIF file with a VVC track to trigger an out-of-bounds heap read. The issue was not detected during the original fix due to lack of testing edge cases where the size parameter approaches UINT32_MAX. Version 1.22.0 of libheif includes a patch for this vulnerability.
Potential Impact
Successful exploitation can cause an out-of-bounds heap read, potentially leading to information disclosure or application instability. The CVSS 4.0 score is 6.8 (medium severity), reflecting local attack vector with low complexity, no privileges required, user interaction needed, and high impact on availability.
Mitigation Recommendations
Version 1.22.0 of libheif patches this vulnerability. Users and maintainers should upgrade to libheif 1.22.0 or later to remediate this issue. No other official remediation or temporary fixes are documented. Patch status is confirmed by the vendor's versioning information.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-05-18T22:54:18.273Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a5fe6d09c2644c7f8cb09d2
Added to database: 07/21/2026, 21:38:24 UTC
Last enriched: 07/22/2026, 08:54:50 UTC
Last updated: 07/31/2026, 19:22:59 UTC
Views: 16
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