# CVE-2021-4461: Seeyon Zhiyuan OA Web Application System < 7.0 SP1 Authentication Bypass

> Attackers can bypass authentication to assign sessions to arbitrary user IDs, leading to account takeover in Seeyon Zhiyuan OA systems.

- **Severity:** Critical 9.3 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 30 Oct 2025
- **Updated:** 28 Nov 2025
- **Also known as:** GHSA-vjp9-58v6-m6fw

## What is CVE-2021-4461?

CVE-2021-4461 is a critical authentication bypass vulnerability in Seeyon Zhiyuan OA Web Application System, published on 30 Oct 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2021-4461?


## How do I fix CVE-2021-4461?

No fix has been published for CVE-2021-4461 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-4461 being exploited?

There is no known exploitation of CVE-2021-4461 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-4461 and fix it if it is affected.

What it is: CVE-2021-4461 is a critical authentication bypass vulnerability in Seeyon Zhiyuan OA Web Application System, published on 30 Oct 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-4461 in the wild and no public exploit code.

Affected product: Seeyon Zhiyuan OA Web Application System. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-4461/ (Markdown: https://insights.sbomify.com/CVE-2021-4461/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-4461
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-4461
- OSV: https://osv.dev/vulnerability/CVE-2021-4461

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-4461/
Summaries are generated and may contain mistakes; the official description above is the record.