{"id":"CVE-2026-39886","summary":"OpenEXR has HTJ2K Signed Integer Overflow in ht_undo_impl()","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`.","aliases":["GHSA-r3mr-mx8q-jcw5"],"modified":"2026-07-15T01:49:14.188586368Z","published":"2026-04-21T01:27:01.371Z","related":["openSUSE-SU-2026:10665-1"],"database_specific":{"cwe_ids":["CWE-190"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39886.json","cna_assigner":"GitHub_M"},"references":[{"type":"WEB","url":"https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.10"},{"type":"ADVISORY","url":"https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-r3mr-mx8q-jcw5"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39886.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-39886"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/academysoftwarefoundation/openexr","events":[{"introduced":"20a65852895894434bea88613f6d29ac8e88bd6e"},{"fixed":"67de2bffbd7da508f75fbdc56e6e551a4e31fb83"}],"database_specific":{"cpe":"cpe:2.3:a:openexr:openexr:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"3.4.0"},{"fixed":"3.4.10"}],"source":["AFFECTED_FIELD","CPE_RANGE","REFERENCES"]}}],"versions":["v3.4.9","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/cve-osv-conversion/osv-output/CVE-2026-39886.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"}]}