CVE-2026-49143 — BrowserStack Runner 0.9.5 Unauthenticated RCE via /_log HTTP Handler
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 arbi…
Published: 2026-06-02 · CVSS: 8.7 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7