CVE-2021-4461

Seeyon Zhiyuan OA Web Application System < 7.0 SP1 Authentication Bypass

CRITICAL 9.3EPSS 0.5%

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.

Affected: Seeyon · Zhiyuan OA Web Application System
CVSS v4.0 VULNCHECK: 9.3 CRITICALCVSS: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
EPSS: 0.49% chance of exploitation in the next 30 days, 41st percentile
Published: 2025-10-30
Updated: 2025-11-28

Proof-of-concept exploits (3)

https://mp.weixin.qq.com/s/0AqdfTrZUVrwTMbKEKresg
chaitin/xray/blob/f90cf321bc4d294bbf6625a9c4853f3bfdf0a384/pocs/seeyon-oa-cookie-leak.yml11760★ · 2024-10-29
projectdiscovery/nuclei-templates/blob/1ca6b8e6fe225cbd46dcb893dcaee01447afa8c0/http/misc…13104★ · 2026-10-16

CVE-2021-4461

Proof-of-concept exploits (3)

References

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