Pillow: BMP RLE decoder memory-amplification DoS via unbounded delta escape / absolute mode

{
  "id": "16388d1e026a92a3eb06b65d15db15d3fe0cf32fac1150f2d0cfd62cf9bd5597",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-96638",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Pillow: BMP RLE decoder memory-amplification DoS via unbounded delta escape / absolute mode",
    "summary": "Pillow is a Python imaging library. From 9.1.0 until 13.0.0, BmpRleDecoder.decode() in src/PIL/BmpImagePlugin.py permits crafted RLE BMP delta escapes and absolute-mode runs to append beyond the remaining dest_length without a per-branch cap. A delta can add roughly 255 image rows in one iteration, so a kilobyte-sized file with a large but permitted width can expand the data bytearray to hundreds of megabytes or more, causing memory-exhaustion denial of service. This issue is fixed in version 13.0.0.",
    "evidence": "cve:CVE-2026-96638",
    "products": [
      {
        "name": {
          "value": "Pillow",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-96638",
      "aliases": [
        "CVE-2026-96638"
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "scope": "UNCHANGED",
            "version": "3.1",
            "baseScore": 6.5,
            "attackVector": "NETWORK",
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H",
            "integrityImpact": "NONE",
            "userInteraction": "REQUIRED",
            "attackComplexity": "LOW",
            "availabilityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "confidentialityImpact": "NONE"
          }
        }
      ],
      "affected": [
        {
          "vendor": "python-pillow",
          "product": "Pillow",
          "versions": [
            {
              "status": "affected",
              "version": ">= 9.1.0, < 13.0.0"
            }
          ]
        }
      ],
      "modified": "2026-10-28T18:21:53.700Z",
      "provider": "cve",
      "references": [
        "https://github.com/python-pillow/Pillow/security/advisories/GHSA-24rc-8hj2-v98c",
        "https://github.com/python-pillow/Pillow/pull/10015",
        "https://github.com/python-pillow/Pillow/commit/e7794835e323ff2691d9b3a974cade1a44301b9a",
        "https://github.com/python-pillow/Pillow/releases/tag/13.0.0"
      ],
      "provider_metadata": {
        "adp": [
          {
            "title": "CISA ADP Vulnrichment",
            "metrics": [
              {
                "other": {
                  "type": "ssvc",
                  "content": {
                    "id": "CVE-2026-96638",
                    "role": "CISA Coordinator",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "version": "2.0.3",
                    "timestamp": "2026-10-28T18:20:26.959004Z"
                  }
                }
              }
            ],
            "providerMetadata": {
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP",
              "dateUpdated": "2026-10-28T18:21:53.700Z"
            }
          }
        ],
        "cna": {
          "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
          "shortName": "GitHub_M",
          "dateUpdated": "2026-10-21T20:47:21.767Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-96638",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 472584,
  "published_at": "2026-10-21T20:47:21.767+00:00"
}