CVE-2026-32740

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

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

strukturag · libheif

CVSS v3.1 CNA

8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS

0.76% chance of exploitation in the next 30 days, 54th percentile

Published

2026-05-19

Updated

2026-07-15

Proof-of-concept exploits (1)

• FORTBRIDGE-UK/libheif-grid-nextjs-rce1★ · 2026-09-27

Security advisories

• strukturag/libheif/security/advisories/GHSA-frfr-f3vg-2g6j
• strukturag/libheif/releases/tag/v1.22.0

References

• CVE Record
• NVD entry

Related

• CVE-2021-22968
• CVE-2026-75604