CVE-2026-41071: libheif: Heap buffer over-read in SampleAuxInfoReader via crafted HEIF sequence file with mismatched saiz sample count

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-05-22 · updated 2026-07-23
Weakness: CWE-125

Description

libheif is a HEIF and AVIF file format decoder and encoder. In versions 1.21.2 and prior, a crafted HEIF sequence file where the saiz box declares more samples than actually exist in the track's chunk table causes a heap-buffer-overflow (out-of-bounds read) in the SampleAuxInfoReader constructor. The SampleAuxInfoReader constructor iterates over saiz->get_num_samples() samples but doesn't validate that this count is consistent with the number of chunks in the chunks vector. When saiz declares more samples than the chunks cover, the loop increments current_chunk past chunks.size(), causing an out-of-bounds read on the chunks vector. The vulnerability is triggered during file parsing (heif_context_read_from_file) without any additional user interaction. Any application using libheif to open untrusted HEIF files is affected. This issue has been fixed in version 1.22.0.

Affected products

strukturag libheif: before 1.22.0 — fixed in 1.22.0

How to fix

Upgrade to a fixed version: strukturag libheif 1.22.0. Check the vendor advisory for mitigations.

References

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