OpenEXR is the reference implementation and specification for the EXR image format, widely used in the motion picture industry. In versions 3.4.0 through 3.4.11, an integer overflow in ht_undo_impl() in src/lib/OpenEXRCore/internal_ht.cpp leads to a heap-buffer overflow when decoding a crafted HTJ2K-compressed EXR file. decode->channels[i].width (int32_t) is multiplied by bytes_per_element in 32-bit signed arithmetic. With large widths (e.g., >= 536870912 for FLOAT data), this overflows, producing a corrupted offset that is later used for pointer arithmetic and can cause a heap out-of-bounds write. The same unchecked multiplication pattern appears in two other HTJ2K paths (bytes-per-line accumulation and pixel-line pointer advancement). As with related CVE-2026-34378 through CVE-2026-34589 fixes in other codecs, validating only after the multiplication is too late because the value may already be overflowed. This issue has been fixed in version 3.4.12.
Fix
Patch, vendor advisory and mitigation references on NVD 2
- https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-777r-f9x8-7r84 Exploit, Mitigation, Patch, Vendor Advisory
- https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-777r-f9x8-7r84 Exploit, Mitigation, Patch, Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 7.1 · openexrNVD modified 2026-10-26 11:10
Affected (CPE criteria) 1
cpe:2.3:a:openexr:openexr:*:*:*:*:*:*:*:*
References 3
- https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.12 Release Notes
- https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-777r-f9x8-7r84 Exploit, Mitigation, Patch, Vendor Advisory
- https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-777r-f9x8-7r84 Exploit, Mitigation, Patch, Vendor Advisory