CVE-2026-49143BrowserStack Runner 0.9.5 Unauthenticated RCE via /_log HTTP Handler
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 8.8 HIGH (v3.1, CNA)CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-94
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- VulnCheck
- NVD analysis
- Deferred
- Record last updated
- Oct 8, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
browserstack browserstack-runner browserstack:runner (from the name) | through 0.9.5 | CNA record |
References
- https://github.com/browserstack/browserstack-runner/security/advisories/GHSA-6vr3-7wcx-v5g5vendor-advisory
- https://www.vulncheck.com/advisories/browserstack-runner-unauthenticated-rce-via-log-http-handlerthird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.