CVE-2026-34379

CVE-2026-34379 · OpenEXR has a misaligned write in LossyDctDecoder_execute leading to undefined behavior (DWA/DWAB decompression)

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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, a misaligned memory write vulnerability exists in LossyDctDecoder_execute() in src/lib/OpenEXRCore/internal_dwa_decoder.h:749. When decoding a DWA or DWAB-compressed EXR file containing a FLOAT-type channel, the decoder performs an in-place HALF→FLOAT conversion by casting an unaligned uint8_t * row pointer to float * and writing through it. Because the row buffer may not be 4-byte aligned, this constitutes undefined behavior under the C standard and crashes immediately on architectures that enforce alignment (ARM, RISC-V, etc.). On x86 it is silently tolerated at runtime but remains exploitable via compiler optimizations that assume aligned access. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.

CVSS 7.1 · High · EPSS 0.3% · Fix available

Published

2026-04-06T15:21:06.556Z

Updated

2026-07-15T01:04:28.373Z

Stack: system

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