{"id":"CVE-2026-39886","published":"2026-04-21T01:27:01Z","modified":"2026-04-21T13:49:21Z","title":"OpenEXR has HTJ2K Signed Integer Overflow in ht_undo_impl()","vendor":"AcademySoftwareFoundation","product":"openexr","tier":"tail","description":{"text":"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`.","provenance":"source","from":"CVE.org"},"cvss":{"score":5.3,"severity":"MEDIUM","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","provenance":"source","from":"CVE.org CNA"},"epss":{"score":0.00302,"percentile":0.22894,"provenance":"source"},"cwes":[{"id":"CWE-190","name":"Integer Overflow or Wraparound"}],"references":[{"url":"https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-r3mr-mx8q-jcw5","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.10","tags":["x_refsource_MISC"]}],"priority":{"score":8.3,"factors":[{"name":"EPSS percentile","points":4.58},{"name":"CVSS severity","points":3.71}]},"vendorSlug":"academysoftwarefoundation","affectedVersions":[{"vendor":"AcademySoftwareFoundation","product":"openexr","versions":[">= 3.4.0, < 3.4.10"]}],"euvd":{"id":"EUVD-2026-24041","exploited":false,"provenance":"source"},"lineage":{"familyId":"fam-academysoftwarefoundation-openexr-cve-2026-34545","parents":[{"from":"CVE-2026-34545","to":"CVE-2026-39886","relation":"incomplete-fix","confidence":"high","kind":"lineage","evidence":[{"kind":"text","provenance":"source","relation":"incomplete-fix","quote":"The CVE-2026-34545 fix did not touch the `int bpl` accumulator at line 211, which is the subject of this advisory.","from":"CVE.org","in":"CVE-2026-39886"}]},{"from":"CVE-2026-34588","to":"CVE-2026-39886","relation":"incomplete-fix","confidence":"high","kind":"lineage","evidence":[{"kind":"text","provenance":"source","relation":"incomplete-fix","quote":"The CVE-2026-34588 fix did not touch `internal_ht.cpp`.","from":"CVE.org","in":"CVE-2026-39886"}]}]}}