{"id":"CVE-2021-4461","state":"PUBLISHED","title":"Seeyon Zhiyuan OA Web Application System < 7.0 SP1 Authentication Bypass","description":"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.","publishedAt":"2025-10-30T21:16:23.161Z","updatedAt":"2025-11-28T19:17:19.543Z","severity":{"score":9.3,"label":"Critical","version":"4.0","vector":"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","source":"VulnCheck"},"assigner":"VulnCheck","products":["Seeyon Zhiyuan OA Web Application System"],"affected":[{"vendor":"Seeyon","product":"Zhiyuan OA Web Application System","defaultStatus":"unknown","versions":[{"version":"0","status":"affected","lessThanOrEqual":"7.0 SP1","versionType":"custom"}],"modules":["thirdpartyController.do – `enc` parameter decoding (LightWeightEncoder) and parsing"]}],"references":["https://mp.weixin.qq.com/s/0AqdfTrZUVrwTMbKEKresg","https://github.com/chaitin/xray/blob/f90cf321bc4d294bbf6625a9c4853f3bfdf0a384/pocs/seeyon-oa-cookie-leak.yml","https://github.com/projectdiscovery/nuclei-templates/blob/1ca6b8e6fe225cbd46dcb893dcaee01447afa8c0/http/misconfiguration/seeyon-unauth.yaml#L20","https://www.vulncheck.com/advisories/seeyon-zhiyuan-oa-web-application-system-authentication-bypass"],"weaknesses":["CWE-306"],"ingestedAt":"2026-10-29T19:49:23.890Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2021/4xxx/CVE-2021-4461.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2021-4461","state":"PUBLISHED","datePublished":"2025-10-30T21:16:23.161Z","dateUpdated":"2025-11-28T19:17:19.543Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2025-10-30T20:08:37.632Z"},"containers":{"cna":{"title":"Seeyon Zhiyuan OA Web Application System < 7.0 SP1 Authentication Bypass","descriptions":[{"lang":"en","value":"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. 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