CVE-2021-4461

CRITICAL EPSS 44.4%
Published Oct 30, 20258mo ago · Modified Jun 17, 20261w ago
9.3 CVSS 4.0
Critical
Find Similar
Published Oct 30, 2025 8mo ago
Last Modified Jun 17, 2026 1w ago

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.

CVSS Details

Base Score
9.3
Exploitability
—
Impact
—
Vector string
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
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope X

Threat Intelligence

EPSS Exploit Probability
44.4% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 1

CWE-306 Missing Authentication for Critical Function Authentication

References 4

  • github.com https://github.com/chaitin/xray/blob/f90cf321bc4d294bbf6625a9c4853f3bfdf0a384/pocs/seeyon-oa-cookie-leak.yml
  • github.com https://github.com/projectdiscovery/nuclei-templates/blob/1ca6b8e6fe225cbd46dcb893dcaee01447afa8c0/http/misconfiguration/seeyon-unauth.yaml#L20
  • mp.weixin.qq.com https://mp.weixin.qq.com/s/0AqdfTrZUVrwTMbKEKresg
  • vulncheck.com https://www.vulncheck.com/advisories/seeyon-zhiyuan-oa-web-application-system-authentication-bypass

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.