MantisBT has Stored HTML Injection / XSS when displaying Tags in Timeline

{
  "id": "7151c01160eb70da79dd44c4dc20a323d9a976aa9c637a0463ae89559374d2d0",
  "url": "https://osv.dev/vulnerability/CVE-2026-33548",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "MantisBT has Stored HTML Injection / XSS when displaying Tags in Timeline",
    "summary": "Mantis Bug Tracker (MantisBT) is an open source issue tracker. In version 2.28.0, improper escaping of tag names retrieved from History in Timeline (my_view_page.php) allows an attacker to inject HTML and, if CSP settings permit, achieve execution of arbitrary JavaScript, when displaying a tag that has been renamed or deleted. Version 2.28.1 contains a patch. Workarounds include editing offending History entries (using SQL) and wrapping `$this->tag_name` in a string_html_specialchars() call in IssueTagTimelineEvent::html().",
    "evidence": "osv:CVE-2026-33548",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-33548",
      "aliases": [
        "CVE-2026-33548",
        "GHSA-73vx-49mv-v8w5"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/mantisbt/mantisbt",
              "type": "GIT",
              "events": [
                {
                  "introduced": "75ed0962f60435d222a04343e60ba319e12093fd"
                },
                {
                  "fixed": "f32787c14d4518476fe7f05f992dbfe6eaccd815"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "= 2.28.0"
                      },
                      {
                        "last_affected": "= 2.28.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandaloneSingleVersion"
                  },
                  {
                    "range": [
                      {
                        "fixed": "f32787c14d4518476fe7f05f992dbfe6eaccd815"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "2.28.0",
            "= 2.28.0",
            "release-2.28.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33548.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:45.583367279Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33548.json",
        "https://github.com/mantisbt/mantisbt/security/advisories/GHSA-73vx-49mv-v8w5",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-33548",
        "https://github.com/mantisbt/mantisbt/commit/f32787c14d4518476fe7f05f992dbfe6eaccd815"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-79"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33548.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-33548",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 513732,
  "published_at": "2026-03-23T19:15:18.891+00:00"
}