# CVE-2026-4959: OpenBMB XAgent ShareServer WebSocket Endpoint share.py check_user missing authentication

> Attackers can bypass authentication on the XAgent ShareServer WebSocket endpoint by manipulating the interaction_id argument.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 Mar 2026
- **Updated:** 31 Mar 2026
- **Also known as:** GHSA-7355-47hq-rrv2

## What is CVE-2026-4959?

CVE-2026-4959 is a medium-severity missing authorization vulnerability in OpenBMB XAgent, published on 27 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability was found in OpenBMB XAgent 1.0.0. This impacts the function check_user of the file XAgentServer/application/websockets/share.py of the component ShareServer WebSocket Endpoint. Performing a manipulation of the argument interaction_id results in missing authentication. Remote exploitation of the attack is possible. The exploit has been made public and could be used. The vendor was contacted early about this disclosure but did not respond in any way.

Weakness: CWE-306 (Missing Authentication for Critical Functionality), CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-4959?

It affects 1 product.


Products: Openbmb Xagent.

## How do I fix CVE-2026-4959?

No fix has been published for CVE-2026-4959 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-4959 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-4959 exists.

## Other vulnerabilities in OpenBMB XAgent

- [CVE-2024-2007](https://insights.sbomify.com/CVE-2024-2007/): OpenBMB XAgent Privileged Mode sandbox (medium 5.3)
- [CVE-2026-4957](https://insights.sbomify.com/CVE-2026-4957/): OpenBMB XAgent API Key function_handler.py FunctionHandler.handle_tool_call log file (medium 5.1)
- [CVE-2025-6281](https://insights.sbomify.com/CVE-2025-6281/): OpenBMB XAgent community path traversal (medium 5.1)
- [CVE-2026-4958](https://insights.sbomify.com/CVE-2026-4958/): OpenBMB XAgent WebSocket Endpoint replayer.py ReplayServer.send_data authorization (low 2.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-4959 and fix it if it is affected.

What it is: CVE-2026-4959 is a medium-severity missing authorization vulnerability in OpenBMB XAgent, published on 27 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-4959 exists.

Affected product: OpenBMB XAgent. 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-2026-4959/ (Markdown: https://insights.sbomify.com/CVE-2026-4959/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-4959
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-4959
- OSV: https://osv.dev/vulnerability/CVE-2026-4959

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-4959/
Summaries are generated and may contain mistakes; the official description above is the record.