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Vulnerability · Published May 19, 2026 · Assigned by GitHub_M

CVE-2026-32740libheif: Heap-Buffer-Overflow Write in Grid Tile Chroma Compositing

High 8.8

In plain English

A high-severity out-of-bounds write in libheif from strukturag. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 53% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.8High
Exploit odds (30 days)0.7%top 47.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack tooling1Public PoC

Official description

libheif is a HEIF and AVIF file format decoder and encoder. Versions 1.21.2 and prior contain a heap-buffer-overflow (write) vulnerability in the grid tile compositing, allowing an attacker to write 64 bytes of fully attacker-controlled data past the end of a chroma plane heap allocation by crafting a HEIF/AVIF file with a 1×4 grid of odd-height tiles. The overflow is triggered during normal image decoding with default build configuration. The written bytes are chroma (Cb/Cr) pixel values from the attacking tile, giving the attacker full control over the overflow content. This issue has been fixed in version 1.22.0.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.23libheif1.23.0-r0ALPINE-CVE-2026-32740
Alpine:v3.24libheif1.22.2-r0ALPINE-CVE-2026-32740
Debian:12libheifno fix listedDEBIAN-CVE-2026-32740
Debian:13libheif1.19.8-1+deb13u1DEBIAN-CVE-2026-32740
Debian:14libheif1.23.1-1DEBIAN-CVE-2026-32740
Ubuntu:25.10libheif1.20.2-1ubuntu0.4UBUNTU-CVE-2026-32740
Ubuntu:26.04:LTSlibheif1.21.2-3ubuntu0.1UBUNTU-CVE-2026-32740

Affected products (as reported)

VendorProductVersions
strukturag libheif < 1.22.0

Weakness: CWE-787 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

References