{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "0"
                  },
                  {
                    "last_affected": "7.0"
                  }
                ],
                "source": "DESCRIPTION"
              }
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "cb5d5b9f0d0290b4343199defc8837aa7b39bf6e"
            }
          ],
          "repo": "https://github.com/projectdiscovery/nuclei-templates",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {},
  "details": "Seeyon Zhiyuan OA Web Application System versions up to and including 7.0 SP1 improperly decode and parse the `enc` parameter in thirdpartyController.do. The decoded map values can influence session attributes without sufficient authentication/authorization checks, enabling attackers to assign a session to arbitrary user IDs. VulnCheck has observed this vulnerability being exploited in the wild as of 2025-10-30 at 00:30:40.855917 UTC.",
  "id": "CVE-2021-4461",
  "modified": "2026-10-20T10:30:29.058948989Z",
  "published": "2025-10-30T22:15:41.633Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/chaitin/xray/blob/f90cf321bc4d294bbf6625a9c4853f3bfdf0a384/pocs/seeyon-oa-cookie-leak.yml"
    },
    {
      "type": "WEB",
      "url": "https://github.com/projectdiscovery/nuclei-templates/blob/1ca6b8e6fe225cbd46dcb893dcaee01447afa8c0/http/misconfiguration/seeyon-unauth.yaml#L20"
    },
    {
      "type": "WEB",
      "url": "https://mp.weixin.qq.com/s/0AqdfTrZUVrwTMbKEKresg"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.vulncheck.com/advisories/seeyon-zhiyuan-oa-web-application-system-authentication-bypass"
    }
  ],
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}