Bug 2538121 (CVE-2026-84383)

Summary:	CVE-2026-84383 libheif: libheif: Heap buffer overflow in `scale_nearest_neighbor()` via duplicate Alpha planes from nested `iden`/`auxl` items
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	urgent	Docs Contact:
Priority:	urgent
Version:	unspecified	CC:	bbrownin, cdrage, eborisov, lball, ngough, rhel-process-autobot, rushinde, veshanka, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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Doc Text:	A critical heap buffer overflow vulnerability exists in libheif versions 1.22.0 through 1.23.1. When decoding a maliciously crafted HEIF, HEIC, or AVIF file using nested iden and auxl references, HeifPixelImage::transfer_channel_from_image_as() can inappropriately append duplicate Alpha planes with differing bit depths. Consequently, scale_nearest_neighbor() in libheif/image/pixelimage.cc allocates an 8-bit destination Alpha plane but writes 10-bit or 12-bit uint16_t samples into it. This allows an unauthenticated remote attacker to trigger an out-of-bounds heap write via heif_decode_image(), which can be leveraged for arbitrary code execution. The issue is resolved in version 1.23.2.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
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Description OSIDB Bzimport 2026-09-22 17:10:25 UTC

libheif is a HEIF and AVIF file format decoder and encoder. From 1.22.0 until 1.23.2, a crafted HEIF, HEIC, or AVIF item graph using nested iden and auxl references can make HeifPixelImage::transfer_channel_from_image_as() append duplicate Alpha planes with different bit depths to m_storage. HeifPixelImage::scale_nearest_neighbor() in libheif/image/pixelimage.cc allocates the destination Alpha plane using the first plane's 8-bit depth, then iterates a later 10-bit or 12-bit Alpha component and writes uint16_t samples into the same 8-bit allocation. The output geometry controls the overflow extent and the encoded sample values control the data written, allowing a remote file processed by heif_decode_image() to cause a heap out-of-bounds write. This issue is fixed in version 1.23.2.