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Tencent BrowserSkill through 0.4.2 Missing Authentication in Local WebSocket Transport

Affects Tencent BrowserSkill through 0.4.2 in its default local-only mode, where the daemon socket is opened without a credential. The checked facts list no fix.

Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.

7.2HighCNA
Exploited
No known exploitation
Fix
Fix or patch referenced
Who is exposed
Specific setups only

Do first: Check whether your setup matches what the bug needs. The extension runs in default local-only mode, with no remote endpoint paired, so the daemon socket is opened without a credential.

Published
Last modified
12/100 · provisional
Specific setups only
None on Exploit-DB, Metasploit or GitHub

Summary

Tencent BrowserSkill through 0.4.2 has a missing authentication flaw in its local WebSocket transport that lets a local attacker impersonate the bsk daemon by binding its port before it starts or after it exits. The attacker can then receive the extension's tool surface, including an evaluate function that runs JavaScript in logged-in browser tabs.

Read the original description

Tencent BrowserSkill through 0.4.2 contains a missing authentication vulnerability that allows local attackers to impersonate the bsk daemon because remoteSocket() connects to the loopback WebSocket without credentials or peer verification. Attackers who bind the daemon port before it starts or after it exits receive the extension's full tool surface, including evaluate, to run JavaScript through CDP in logged-in browser tabs.

cve.now Index

12Pcve.now Index 12 of 100 · methodology v3 · provisional
  • Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
  • Exposure5/25Specific setups only
  • Reach?/20Unknown. No tracked technology or package matched
  • Severity7.2/10CVSS 7.2
  • No patch0/5No signal

What would change the score

  • Would score about 62 if added to CISA KEV
  • Would score about 57 if CISA's SSVC rates exploitation active
  • Would score about 22 if CISA's SSVC rates it automatable

What to do

  • Check whether your setup matches what the bug needs.

    The extension runs in default local-only mode, with no remote endpoint paired, so the daemon socket is opened without a credential.
  • Apply the patch listed under Evidence.

Timeline

  1. CVE published
  2. First seen by cve.now

Affected versions

  • Tencent BrowserSkill

    through 0.4.2

Evidence 5

  1. Patch
  2. Report
  3. Repository
  4. Repository
  5. Link

Corrections

None so far.

Something wrong on this page? Report an error. Every fix is listed here.

Questions about CVE-2026-125361

Is CVE-2026-125361 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

What does this mean?

A local process can impersonate the bsk daemon on the local WebSocket. That gives it control of the extension's full tool surface, including running arbitrary JavaScript in tabs of the user's logged-in browser profile.Source: github.com

Which versions are affected by CVE-2026-125361?

BrowserSkill: through 0.4.2.Source: cve.now feed data

Am I affected, and how do I check?

Versions through 0.4.2 are in scope. The exposure applies in the default local-only mode, where no remote endpoint is paired and the socket is opened with no credential. To check a setup, look at the installed BrowserSkill version and whether a remote endpoint is paired.Source: github.com

How do I fix CVE-2026-125361?

The checked facts do not name a fixed version or a workaround, so no upgrade target can be given. Check the vendor for a release later than 0.4.2.Source: github.com