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CVE-2026-62863: MoLing before 0.5.0 lets attackers hijack tool sessions

CVE-2026-62863 · published 1 day ago

Summary

In versions prior to 0.5.0, MoLing’s SSE mode does not check who is calling its /sse and /message web endpoints, and it allows any website to read data from them. A malicious web page can capture a session identifier and then use it to issue unauthorized commands, potentially reading or changing files or running code on the host. Upgrade to version 0.5.0 or later to add the required authentication and stop the cross‑origin access.

Original advisory text

MoLing: unauthenticated SSE and wildcard CORS expose tool sessions

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.

References

https://github.com/gojue/moling/commit/ae07f704cbc88d4419fc0fbaec278090fcd0502d Patch
https://github.com/gojue/moling/pull/48 Patch
https://github.com/gojue/moling/releases/tag/v0.5.0 URL
https://github.com/gojue/moling/security/advisories/GHSA-qpgh-hp5g-4vwp Vendor Advisory
https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/62xxx/CVE-2026-62863... Vendor Advisory
https://nvd.nist.gov/vuln/detail/CVE-2026-62863 Vendor Advisory

Fix within

Internet-facing 14 days

Internal At next upgrade

Not known to be exploited
Needs hands-on effort to exploit (estimated)
Gives an attacker full control (estimated)

Severity

9.6 Critical

Exploitation

<1% chance of attack within 30 days

Type

CWE-306Missing Authentication for Critical Function

CWE-942Permissive Cross-domain Security Policy with Untrusted Domains

Timeline

Published30 Oct 2026

Updated31 Oct 2026

First seen30 Oct 2026

Sources

CVE-2026-62863 · NVD

CVE-2026-62863 · OSV

GHSA-qpgh-hp5g-4vwp · GHSA

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