{"id":"JLSEC-2026-806","summary":"Reading malicious EXR files can cause out-of-bounds writes","details":"OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. Versions 3.4.0 through 3.4.9 have a signed integer overflow vulnerability in OpenEXR's HTJ2K (High-Throughput JPEG 2000) decompression path. The `ht_undo_impl()` function in `src/lib/OpenEXRCore/internal_ht.cpp` accumulates a bytes-per-line value (`bpl`) using a 32-bit signed integer with no overflow guard. A crafted EXR file with 16,385 FLOAT channels at the HTJ2K maximum width of 32,767 causes `bpl` to overflow `INT_MAX`, producing undefined behavior confirmed by UBSan. On an\nallocator-permissive host where the required ~64 GB allocation succeeds, the wrapped negative `bpl` value would subsequently be used as a per-scanline pointer advance, which would produce a heap out-of-bounds write. On a memory-constrained host, the allocation fails before `ht_undo_impl()` is entered. This is the second distinct integer overflow in `ht_undo_impl()`. CVE-2026-34545 addressed a different overflow in the same function — the `int16_t p` pixel-loop counter at line ~302 that overflows when iterating over channels whose `width` exceeds 32,767. The CVE-2026-34545 fix did not touch the `int bpl` accumulator at line 211, which is the subject of this advisory. The `bpl` accumulator was also not addressed by any of the 8 advisories in the 2026-04-05 v3.4.9 release batch. This finding is structurally identical to CVE-2026-34588 (PIZ `wcount*nx` overflow in `internal_piz.c`) and should be remediated with the same pattern. The CVE-2026-34588 fix did not touch `internal_ht.cpp`. Version 3.4.10 contains a remediation that addresses the vulnerability in `internal_ht.cpp`.","modified":"2026-07-29T14:30:03.952416568Z","published":"2026-07-29T14:18:08.707Z","upstream":["CVE-2026-39886"],"database_specific":{"license":"CC-BY-4.0","sources":[{"imported":"2026-07-29T13:22:20.825Z","modified":"2026-06-17T10:42:45.270Z","published":"2026-04-21T02:16:07.753Z","url":"https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-39886","html_url":"https://nvd.nist.gov/vuln/detail/CVE-2026-39886","database_specific":{"status":"Analyzed"},"id":"CVE-2026-39886"}]},"references":[{"type":"WEB","url":"https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.10"},{"type":"WEB","url":"https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-r3mr-mx8q-jcw5"}],"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-2026-806.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"}]}