PT-2026-45857 · Browserstack · Browserstack-Runner

Christ Bouchuen · Published 2026-06-02 · Updated 2026-06-02 · CVE-2026-49143

Mitre

CVSS v3.1

8.8

High

Base vector

AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

BrowserStack Runner through 0.9.5 contains a remote code execution vulnerability in the / log HTTP handler that allows unauthenticated network-adjacent attackers to execute arbitrary code by submitting crafted JSON request bodies to the handler, which passes user-supplied data to vm.runInNewContext() combined with eval(). Attackers can escape the Node.js vm sandbox by leveraging a host-context Function reference through util.format to access the host process via this.constructor.constructor, achieving full remote code execution on the underlying system without any authentication.

Fix

Code Injection

Weakness Enumeration

CWE-94

Related Identifiers

CVE-2026-49143

Affected Products

Browserstack-Runner

References · 3

• https://github.com/browserstack/browserstack-runner/security/advisories/GHSA-6vr3-7wcx-v5g5 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-49143 · Security Note
• https://vulncheck.com/advisories/browserstack-runner-unauthenticated-rce-via-log-http-handler · Note