Описание
OpenEXR: DWA Lossy Decoder Heap Out-of-Bounds Write
Summary
The DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store.
This bug is reachable from the public decoder path and can be reproduced through the shipped exrcheck tool with a crafted scanline DWAA file. The confirmed dynamic symptom is a write-side crash in the lossy DCT execution path.
Tested on commit: 7820b7e1b93405ba1d551c43a945018226b75bc5
Root Cause and Data Flow
The vulnerable pointer construction lives in src/lib/OpenEXRCore/internal_dwa_decoder.h:
The expression numBlocksX * 64 is computed as signed int. Once numBlocksX is large enough, the multiplication wraps, and rowBlock[comp] points backward rather than forward into the temporary decode buffer.
Later, LossyDctDecoder_execute() uses those derived pointers for real loads and stores during the block shuffle and reconstruction process. At that point the decoder is no longer operating within the bounds of the allocation created for rowBlockHandle.
The public control flow is the standard one:
UBSan gives a clean root-cause diagnosis on the overflowing multiply, while ASAN shows the later memory error in the write-side decode path.
Reproduction
Build with exrcheck with ASAN and run:
Found by: Quang Luong of Calif.io
Ссылки
- https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-p8xc-w3q4-h64x
- https://nvd.nist.gov/vuln/detail/CVE-2026-34589
- https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.2.7
- https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.3.9
- https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.9
Пакеты
OpenEXR
>= 3.2.0, < 3.2.7
3.2.7
OpenEXR
>= 3.3.0, < 3.3.9
3.3.9
OpenEXR
>= 3.4.0, < 3.4.9
3.4.9
Связанные уязвимости
OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, the DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.
OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, the DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.
OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, the DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.
OpenEXR provides the specification and reference implementation of the ...
