Seeyon Zhiyuan OA Web Application System < 7.0 SP1 Authentication Bypass

Advisories

severity: critical
date: October 30, 2025
Affecting: Zhiyuan OA Web Application System <= 7.0 SP1
An affected versions range is undefined, and it is unknown if this vulnerability has been patched.
CVE: CVE-2021-4461
CWE: CWE-306 Missing Authentication for Critical Function
CVSS: 9.3
CVSS V4 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
References: WeChat Disclosure
Nuclei Template
chaitin/xray GitHub PoC
Credit: Anonymous User via WeChat
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.