Published April 6, 2026 · Updated April 6, 2026
CVE-2026-34379 is a high-severity vulnerability affecting versions of OpenEXR prior to 3.2.7, 3.3.9, and 3.4.9. The issue arises from a misaligned memory write in the LossyDctDecoder_execute() function when decoding certain compressed EXR files, potentially leading to application crashes or exploitation on specific architectures. Organizations using affected versions should update to the patched versions immediately to mitigate risks associated with this vulnerability.
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.
CVE-2026-34379 is a critical vulnerability in OpenEXR impacting versions 3.2.0-3.4.8, causing potential crashes and exploitation. Immediate updates are essential.