MapServer: NULL pointer dereference in SLD `` rule parsing reachable via WMS `SLD_BODY`

{
  "id": "5e3965632d283e9933ae7e7947d2e52a6e5410ff3ef4bd2e318ec8b7c2c1a35b",
  "url": "https://osv.dev/vulnerability/CVE-2026-45104",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "MapServer: NULL pointer dereference in SLD `` rule parsing reachable via WMS `SLD_BODY`",
    "summary": "MapServer is a system for developing web-based GIS applications. From 6.4.0 to before 8.6.3, msSLDParseUserStyle always calls _SLDApplyRuleValues(psRule, psLayer, 1); for any carrying — it assumes msSLDParseRule added one class. When the rule has no symbolizer (a structurally valid SLD), msSLDParseRule adds zero, and _SLDApplyRuleValues ends up indexing _class[-1], resulting in a NULL pointer dereference. A 200-byte well-formed SLD via the WMS SLD_BODY= parameter is enough to trigger this, no auth required. This vulnerability is fixed in 8.6.3.",
    "evidence": "osv:CVE-2026-45104",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-45104",
      "aliases": [
        "CVE-2026-45104",
        "GHSA-4h8g-378q-r75m"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/mapserver/mapserver",
              "type": "GIT",
              "events": [
                {
                  "introduced": "a098e546885dd7244ce6174ec11e6f0410879a41"
                },
                {
                  "fixed": "d83a1b9ce1301e6f941a1a8ea787fd209f7ecfba"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "6.4.0"
                      },
                      {
                        "fixed": "8.6.3"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "cpe": "cpe:2.3:a:osgeo:mapserver:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "6.4.0"
                      },
                      {
                        "fixed": "8.6.3"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "rel-8-6-2",
            "rel-8-6-1",
            "rel-8-6-0",
            "rel-8-6-0-rc1",
            "rel-8-6-0-beta2",
            "rel-8-6-0-beta1",
            "rel-6-4-0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-45104.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:50.174084362Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45104.json",
        "https://github.com/MapServer/MapServer/security/advisories/GHSA-4h8g-378q-r75m",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-45104"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-129",
          "CWE-476"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45104.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-45104",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 518423,
  "published_at": "2026-05-27T18:41:39.396+00:00"
}