CVE-2026-84451: strukturag libheif Out-of-bounds Read

Vulnerability summary

CVE-2026-84451 is a medium (CVSS 6.5) Out-of-bounds Read vulnerability in strukturag libheif. EPSS estimates a 0.31% chance of exploitation in the next 30 days, higher than 22.4% of scored vulnerabilities.

Timeline

1. 18-09-2026
   PublishedVulnerability first disclosed.
2. 24-09-2026
   Last modifiedVulnerability information updated.

Description

libheif is a HEIF and AVIF file format decoder and encoder. From 1.19.0 until 1.23.3, the no-icef full-item branch of unc_decoder::get_compressed_image_data_uncompressed() in libheif/codecs/uncompressed/unc_decoder.cc retains an addition-based range check that can wrap when a crafted uncompressed tile grid produces a large range_start_offset and range_size. The overflow makes the bounds comparison pass and allows heif_image_handle_decode_image_tile() to call memcpy() with an invalid source pointer and a very large length when decoding a valid high-index advertised tile. This incomplete remediation of CVE-2026-62292 can reliably crash tile-processing applications, while whole-image decoding is not claimed to reach the demonstrated path. This issue is fixed in version 1.23.3.

• CWE-125Out-of-bounds ReadThe product reads data past the end, or before the beginning, of the intended buffer.