CVE-2026-34379

Summary

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.

Affected Software

VendorProductVersion RangeStatus
AcademySoftwareFoundationopenexr>= 3.2.0, < 3.2.7affected
AcademySoftwareFoundationopenexr>= 3.3.0, < 3.3.9affected
AcademySoftwareFoundationopenexr>= 3.4.0, < 3.4.9affected

Weaknesses

  • CWE-704: CWE-704: Incorrect Type Conversion or Cast
  • CWE-787: CWE-787: Out-of-bounds Write
  • CWE-843: CWE-843: Access of Resource Using Incompatible Type ('Type Confusion')

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: no
    • Technical Impact: partial

OpenEXR: OpenEXR: Denial of Service due to misaligned memory write during EXR file decoding

Additional References

References