strukturag libheif up to 1.21.x Decoder size integer overflow

Summaryinfo

A vulnerability was found in strukturag libheif up to 1.21.x. It has been rated as critical. Impacted is an unknown function of the component Decoder. This manipulation of the argument size causes integer overflow. The identification of this vulnerability is CVE-2026-47251. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability has been found in strukturag libheif up to 1.21.x and classified as critical. Affected by this vulnerability is an unknown function of the component Decoder. The manipulation of the argument size with an unknown input leads to a integer overflow vulnerability. The CWE definition for the vulnerability is CWE-190. The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-47251 since 05/19/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 1.22.0 eliminates this vulnerability.

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Productinfo

Vendor

• strukturag

Name

• libheif

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17
• 1.18
• 1.19
• 1.20
• 1.21

Website

• Product: https://github.com/strukturag/libheif/

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