browserstack browserstack-runner up to 0.9.5 HTTP /_log vm.runInNewContext code injection

Summaryinfo

A vulnerability labeled as critical has been found in browserstack browserstack-runner up to 0.9.5. Affected by this issue is the function vm.runInNewContext of the file /_log of the component HTTP Handler. The manipulation results in code injection. This vulnerability only affects products that are no longer supported by the maintainer. This vulnerability was named CVE-2026-49143. The attack needs to be approached within the local network. There is no available exploit.

Detailsinfo

A vulnerability classified as critical has been found in browserstack browserstack-runner up to 0.9.5. Affected is the function vm.runInNewContext of the file /_log of the component HTTP Handler. The manipulation with an unknown input leads to a code injection vulnerability. CWE is classifying the issue as CWE-94. The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The weakness was presented by Christ Bouchuen as GHSA-6vr3-7wcx-v5g5. The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-49143 since 05/27/2026. The exploitability is told to be easy. The attack needs to be done within the local network. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 06/03/2026). The MITRE ATT&CK project declares the attack technique as T1059.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-34029). Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

• browserstack

Name

• browserstack-runner

Version

• 0.9.0
• 0.9.1
• 0.9.2
• 0.9.3
• 0.9.4
• 0.9.5

Support

• end of life

Website

• Product: https://github.com/browserstack/browserstack-runner/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Once again VulDB remains the best source for vulnerability data.

Discussion