Description
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 products
openexr: openexr
References7
- github.com/AcademySoftwareFoundation/openexr/security/advisorie… ExploitVendor Advisory
- github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.2.7 ProductRelease Notes
- github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.3.9 ProductRelease Notes
- github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.9 ProductRelease Notes
- access.redhat.com/security/cve/CVE-2026-34379
- bugzilla.redhat.com/show_bug.cgi?id=2455402
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34379…
Metrics
- CVSS 3.1
-
7.1
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H - EPSS — exploit probability
- 0% percentile: 22 · as of 12 November 2026
- CWE
- CWE-704CWE-787CWE-843CWE-475
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