OpenEXR has HTJ2K Signed Integer Overflow in ht_undo_impl()

{
  "id": "106a9f142cfc87e814a9eaaffda1cf1b235cbf9c0200ccbb9f66d19e8e6a3c3b",
  "url": "https://osv.dev/vulnerability/CVE-2026-39886",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "OpenEXR has HTJ2K Signed Integer Overflow in ht_undo_impl()",
    "summary": "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 allocator-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",
    "evidence": "osv:CVE-2026-39886",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-39886",
      "aliases": [
        "CVE-2026-39886",
        "GHSA-r3mr-mx8q-jcw5"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/academysoftwarefoundation/openexr",
              "type": "GIT",
              "events": [
                {
                  "introduced": "20a65852895894434bea88613f6d29ac8e88bd6e"
                },
                {
                  "fixed": "67de2bffbd7da508f75fbdc56e6e551a4e31fb83"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "3.4.0"
                      },
                      {
                        "fixed": "3.4.10"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "67de2bffbd7da508f75fbdc56e6e551a4e31fb83"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v3.4.10"
                  },
                  {
                    "cpe": "cpe:2.3:a:openexr:openexr:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "3.4.0"
                      },
                      {
                        "fixed": "3.4.10"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "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"
          }
        }
      ],
      "modified": "2026-10-28T02:30:27.868164264Z",
      "provider": "osv",
      "references": [
        "https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.10",
        "https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-r3mr-mx8q-jcw5",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39886.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-39886"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-190"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39886.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-39886",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 494501,
  "published_at": "2026-04-21T01:27:01.371+00:00"
}