Stored cross-site scripting in Pending Changes sidebar

{
  "id": "f8bc3c32179bd120bb850512ee4b0cce8facc63708633ca9fb21d65f8d4e5bca",
  "url": "https://osv.dev/vulnerability/CVE-2026-20915",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Stored cross-site scripting in Pending Changes sidebar",
    "summary": "Stored cross-site scripting (XSS) in Checkmk version 2.5.0 (beta) before 2.5.0b2 allows authenticated users with permission to create pending changes to inject malicious JavaScript into the Pending Changes sidebar, which will execute in the browsers of other users viewing the sidebar.",
    "evidence": "osv:CVE-2026-20915",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-20915",
      "aliases": [
        "CVE-2026-20915"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:L/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/checkmk/checkmk",
              "type": "GIT",
              "events": [
                {
                  "introduced": "406aa5e6e4301396e7db0a7a763e8db1de64635e"
                },
                {
                  "last_affected": "406aa5e6e4301396e7db0a7a763e8db1de64635e"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:checkmk:checkmk:2.5.0:b1:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "2.5.0-b1"
                      },
                      {
                        "last_affected": "2.5.0-b1"
                      }
                    ],
                    "source": "CPE_STRING"
                  }
                ]
              }
            }
          ],
          "versions": [
            "2.5.0-b1",
            "v2.5.0p1-rc2",
            "v2.5.0p1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-20915.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:48.417529057Z",
      "provider": "osv",
      "references": [
        "https://checkmk.com/werk/19526",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/20xxx/CVE-2026-20915.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-20915"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-79"
        ],
        "cna_assigner": "Checkmk",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "2.5.0b1"
                  },
                  {
                    "fixed": "2.5.0b2"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/20xxx/CVE-2026-20915.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-20915",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 516722,
  "published_at": "2026-03-31T13:51:02.358+00:00"
}