{"id":"CVE-2026-34379","summary":"OpenEXR has a misaligned write in LossyDctDecoder_execute leading to undefined behavior (DWA/DWAB decompression)","details":"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.","aliases":["GHSA-w88v-vqhq-5p24"],"modified":"2026-05-28T03:53:54.207547030Z","published":"2026-04-06T15:21:06.556Z","related":["SUSE-SU-2026:21372-1","openSUSE-SU-2026:10505-1","openSUSE-SU-2026:20605-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34379.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-704","CWE-787","CWE-843"]},"references":[{"type":"WEB","url":"https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.2.7"},{"type":"WEB","url":"https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.3.9"},{"type":"WEB","url":"https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.9"},{"type":"ADVISORY","url":"https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-w88v-vqhq-5p24"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34379.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34379"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/academysoftwarefoundation/openexr","events":[{"introduced":"20a65852895894434bea88613f6d29ac8e88bd6e"},{"fixed":"b5fa98ac6b5fc660c0295123c1d02bbf687dbec3"}]}],"versions":["v3.4.9-rc","v3.4.8-rc","v3.4.8","v3.4.7","v3.4.7-rc","v3.4.6","v3.4.6-rc","v3.4.5","v3.4.5-rc","v3.4.4-rc2","v3.4.4","v3.4.4-rc","v3.4.3-rc3","v3.4.3","v3.4.3-rc2","v3.4.3-rc","v3.4.2-rc2","v3.4.2","v3.4.2-rc","v3.4.1-rc2","v3.4.1","v3.4.1-rc","v3.4.0"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-34379.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H"}]}