libheif: Uninitialized Heap Memory Information Leak via Failed Grid Tiles

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Summary

CVECVE-2026-32814
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-19 21:16:42 UTC
Updated2026-05-20 14:06:33 UTC
Descriptionlibheif is a HEIF and AVIF file format decoder and encoder. In versions 1.21.2 and prior, when decoding a HEIF grid image with strict_decoding=false (the default), a corrupted tile silently fails to decode and the library returns heif_error_Ok with no indication of failure, leading to an uninitialized heap memory information leak. The canvas is allocated via create_clone_image_at_new_size() → plane.alloc() → new (std::nothrow) uint8_t[allocation_size] which does not zero the memory; only the alpha plane is explicitly initialized via fill_plane(), so the Y, Cb, and Cr planes contain whatever was previously at that heap address. The failed tile's region of the canvas is never written. It retains uninitialized heap data that is delivered to the caller as decoded pixel values (4,096 bytes per Y/Cb/Cr plane = 12,288+ bytes total). Any application using libheif to decode grid-based HEIF/AVIF files with default settings is vulnerable: a crafted .heic or .avif file causes 4,096+ bytes of heap memory to appear as pixel values in the decoded image, and the calling application receives heif_error_Ok, so it has no indication the output contains heap garbage. In server-side image processing, an uploaded crafted HEIF decoded and re-encoded (e.g., as PNG/JPEG for thumbnails, CDN, social media) can leak cross-user data such as auth tokens, database results, and other users' image data. This issue has been fixed in version 1.22.0.

Risk And Classification

Primary CVSS: v3.1 6.5 MEDIUM from [email protected]

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

EPSS: 0.000330000 probability, percentile 0.100860000 (date 2026-05-27)

Problem Types: CWE-200 | CWE-908 | CWE-200 CWE-200: Exposure of Sensitive Information to an Unauthorized Actor | CWE-908 CWE-908: Use of Uninitialized Resource

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
3.1CNADECLARED6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Strukturag Libheif affected < 1.22.0 Not specified

References

ReferenceSourceLinkTags
github.com/strukturag/libheif/releases/tag/v1.22.0 [email protected] github.com
github.com/strukturag/libheif/security/advisories/GHSA-4m8r-34pg-rvwc [email protected] github.com
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