libheif is a HEIF and AVIF file format decoder and encoder. Versions 1.21.2 and prior contain a heap buffer over-read in HeifPixelImage::overlay() in libheif/pixelimage.cc. When compositing an overlay image (iovl) whose child image has a different bit depth for the alpha channel than for the color channels, the function indexes into the alpha plane using the color channel stride (in_stride) instead of the previously retrieved alpha_stride, causing reads past the end of the alpha buffer (up to 3,123 bytes for a 100×50 image with 10-bit color and 8-bit alpha). A crafted HEIF file can exploit this to cause a denial of service (crash) or potentially disclose adjacent heap memory through leaked bytes embedded in the decoded output pixels. This issue has been fixed in versionThis issue has been fixed in version 1.22.0.
History

Wed, 20 May 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 20 May 2026 10:15:00 +0000

Type Values Removed Values Added
First Time appeared Struktur
Struktur libheif
Vendors & Products Struktur
Struktur libheif

Wed, 20 May 2026 00:15:00 +0000

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References
Metrics threat_severity

None

threat_severity

Important


Tue, 19 May 2026 20:30:00 +0000

Type Values Removed Values Added
Description libheif is a HEIF and AVIF file format decoder and encoder. Versions 1.21.2 and prior contain a heap buffer over-read in HeifPixelImage::overlay() in libheif/pixelimage.cc. When compositing an overlay image (iovl) whose child image has a different bit depth for the alpha channel than for the color channels, the function indexes into the alpha plane using the color channel stride (in_stride) instead of the previously retrieved alpha_stride, causing reads past the end of the alpha buffer (up to 3,123 bytes for a 100×50 image with 10-bit color and 8-bit alpha). A crafted HEIF file can exploit this to cause a denial of service (crash) or potentially disclose adjacent heap memory through leaked bytes embedded in the decoded output pixels. This issue has been fixed in versionThis issue has been fixed in version 1.22.0.
Title libheif: Heap Buffer OOB Read in overlay compositing due to wrong alpha stride
Weaknesses CWE-125
References
Metrics cvssV3_1

{'score': 7.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-05-19T20:07:21.464Z

Updated: 2026-05-20T17:23:02.780Z

Reserved: 2026-03-16T21:03:44.420Z

Link: CVE-2026-32882

cve-icon Vulnrichment

Updated: 2026-05-20T17:22:08.118Z

cve-icon NVD

Status : Deferred

Published: 2026-05-19T21:16:42.363

Modified: 2026-05-20T18:16:26.880

Link: CVE-2026-32882

cve-icon Redhat

Severity : Important

Publid Date: 2026-05-19T20:07:21Z

Links: CVE-2026-32882 - Bugzilla