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.
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Fix
- Fixed in 0.5.0
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
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.
Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.
Read the original 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.
Timeline
- CVE published
- First seen by cve.now
- Posted on X by cve.now
Affected versions
- gojue moling
fixed in 0.5.0
References 4
GitHub · gojue/moling
Questions about CVE-2026-62863
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: github.com
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: github.com
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: github.com
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: cve.now feed data