Bug 2519006 (CVE-2026-62291)

Summary: CVE-2026-62291 libheif: libheif: Arbitrary code execution via heap corruption in image processing
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in libheif, a library for decoding and encoding HEIF and AVIF image formats. A remote attacker could exploit this vulnerability by providing a specially crafted image sequence with mismatched auxiliary alpha dimensions. During the image processing workflow, this could lead to attacker-controlled heap corruption. This critical issue potentially allows for arbitrary code execution or denial of service.
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Bug Depends On: 2521930, 2521932    
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Description OSIDB Bzimport 2026-08-18 22:03:59 UTC 
libheif is a HEIF and AVIF file format decoder and encoder. In 1.23.0 and earlier, a crafted image sequence with a 2x2 primary plane and a 256x256 auxiliary alpha plane can cause attacker-controlled heap corruption during a normal decode and re-encode workflow. Track_Visual::decode_next_image_sample() calls transfer_channel_from_image_as() without checking that the auxiliary alpha dimensions match the main frame. The resulting inconsistent image reaches heif_track_decode_next_image() and then heif_context_encode_image(). In unc_encoder::encode(), unc_encoder_component_interleave::encode_tile() sizes its buffer with compute_tile_data_size_bytes() using the primary dimensions but copies each component using its actual plane dimensions. The oversized alpha plane is therefore copied beyond the allocation, causing an out-of-bounds write; the inverse size mismatch can also produce an out-of-bounds read. This issue is fixed in version 1.23.1.