Session Management Flaw in Seeyon Zhiyuan OA Web Application System
CVE-2021-4461

9.3CRITICAL

Key Information:

Vendor

Seeyon

Status
Zhiyuan Oa Web Application System
Vendor
CVE Published:
30 October 2025

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2021-4461?

The Seeyon Zhiyuan OA Web Application System, up to version 7.0 SP1, contains a vulnerability in its session management due to improper decoding and parsing of the enc parameter. An attacker can exploit this flaw to manipulate session attributes without proper authentication or authorization, allowing them to assign sessions to arbitrary user IDs. Active exploitation attempts have been reported, raising significant concerns for user data integrity and security.

Affected Version(s)

Zhiyuan OA Web Application System 0 <= 7.0 SP1

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2021-4461 - Proof of Concept

CVE-2021-4461 - Proof of Concept

CVE-2021-4461 - Proof of Concept

References

https://mp.weixin.qq.com/s/0AqdfTrZUVrwTMbKEKresg
exploit
https://github.com/chaitin/xray/blob/f90cf321bc4d294bbf66...
exploit
https://github.com/projectdiscovery/nuclei-templates/blob...
exploit

CVSS V4

Score:
9.3
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Anonymous User via WeChat
JSON
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CVE-2021-4461 : Session Management Flaw in Seeyon Zhiyuan OA Web Application System