{"id":"JLSEC-2026-812","summary":"Heap buffer overflow when decoding a malicious HTJ2K-compressed EXR file","details":"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-\u003echannels[i].width (`int32_t`) is multiplied by `bytes_per_element` in 32-bit signed arithmetic. With large widths (e.g., \u003e= 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.","modified":"2026-07-29T14:30:04.201582017Z","published":"2026-07-29T14:18:08.707Z","upstream":["CVE-2026-44663"],"database_specific":{"license":"CC-BY-4.0","sources":[{"modified":"2026-06-26T02:20:43.437Z","published":"2026-06-18T21:16:28.767Z","url":"https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-44663","html_url":"https://nvd.nist.gov/vuln/detail/CVE-2026-44663","database_specific":{"status":"Analyzed"},"id":"CVE-2026-44663","imported":"2026-07-29T13:22:21.154Z"}]},"references":[{"type":"WEB","url":"https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.12"},{"type":"WEB","url":"https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-777r-f9x8-7r84"},{"type":"WEB","url":"https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-777r-f9x8-7r84"}],"affected":[{"package":{"name":"OpenEXR_jll","ecosystem":"Julia","purl":"pkg:julia/OpenEXR_jll?uuid=18a262bb-aa17-5467-a713-aee519bc75cb"},"ranges":[{"type":"SEMVER","events":[{"introduced":"3.4.4+0"},{"fixed":"3.4.12+0"}]}],"database_specific":{"source":"https://github.com/JuliaLang/SecurityAdvisories.jl/tree/generated/osv/2026/JLSEC-2026-812.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H"}]}