# CVE-2026-125361: Tencent BrowserSkill through 0.4.2 Missing Authentication in Local WebSocket Transport

Status: published. Published: 2026-11-09. Updated: 2026-11-09.

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.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/Tencent/BrowserSkill/commit/7e862a44d19d0c1e492901fe29562cc7d79af590

## Affected products and versions

- Tencent / BrowserSkill (browser-skill): ≥ 0; ≤ 0.4.2 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 7.2 (high); CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 6.3 (medium); CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-923

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/Tencent/BrowserSkill/issues/402 (CNA: VulnCheck; issue-tracking)

- https://github.com/Tencent/BrowserSkill (CNA: VulnCheck; product)

- https://github.com/Tencent/BrowserSkill/blob/ext-v0.4.2/apps/extension/src/transport/remote-endpoint.ts#L79-L85 (CNA: VulnCheck; technical-description)

- https://github.com/Tencent/BrowserSkill/commit/7e862a44d19d0c1e492901fe29562cc7d79af590 (CNA: VulnCheck; patch)

- https://www.vulncheck.com/advisories/tencent-browserskill-through-0.4.2-missing-authentication-in-local-websocket-transport (CNA: VulnCheck; third-party-advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-125361; retrieved 2026-11-10; source updated 2026-11-09

Revision: 5dec6af76a767b84225fc6ce792e882a2507254c4f90c53b777e7e8942a01ef5

Canonical: https://y2.dev/cve/CVE-2026-125361

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