Vikunja: CalDAV and feeds BasicAuth endpoints have no rate limit, bypassing the anti-brute-force floor on account passwords in code.vikunja.io/api

{
  "id": "e5e4e04c1b1bd1eef1fe1330b614f167f0f5e016d394c615c51bef1dc42fdb31",
  "url": "https://osv.dev/vulnerability/GO-2026-6737",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Vikunja: CalDAV and feeds BasicAuth endpoints have no rate limit, bypassing the anti-brute-force floor on account passwords in code.vikunja.io/api",
    "summary": "Vikunja: CalDAV and feeds BasicAuth endpoints have no rate limit, bypassing the anti-brute-force floor on account passwords in code.vikunja.io/api. NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions. (If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.) The additional affected modules and versions are: code.vikunja.io/api before v2.6.0.",
    "evidence": "osv:GO-2026-6737",
    "products": [
      {
        "name": {
          "value": "code.vikunja.io/api",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "GO-2026-6737",
      "aliases": [
        "CVE-2026-91973",
        "GHSA-m469-88xx-8rx2",
        "GO-2026-6737"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "code.vikunja.io/api",
            "purl": "pkg:golang/code.vikunja.io/api",
            "ecosystem": "Go"
          },
          "database_specific": {
            "source": "https://vuln.go.dev/ID/GO-2026-6737.json"
          },
          "ecosystem_specific": {
            "custom_ranges": [
              {
                "type": "ECOSYSTEM",
                "events": [
                  {
                    "introduced": "0"
                  },
                  {
                    "fixed": "2.6.0"
                  }
                ]
              }
            ]
          }
        }
      ],
      "modified": "2026-10-19T21:31:35.964761967Z",
      "provider": "osv",
      "references": [
        "https://github.com/go-vikunja/vikunja/security/advisories/GHSA-m469-88xx-8rx2",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-91973",
        "https://github.com/go-vikunja/vikunja/pull/3688",
        "https://github.com/go-vikunja/vikunja/releases/tag/v2.6.0",
        "https://www.vulncheck.com/advisories/vikunja-before-2.6.0-authentication-bypass-via-caldav-basicauth"
      ],
      "provider_metadata": {
        "url": "https://pkg.go.dev/vuln/GO-2026-6737",
        "review_status": "UNREVIEWED"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-91973",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 376548,
  "published_at": "2026-10-19T21:08:26+00:00"
}