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VulnerabilityPublished Updated

CVE-2026-49143: browserstack-runner · Code Injection

Affects browserstack-runnerSource CVE Database V5

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Not known to be exploited · CVSS 8.7 High.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 4.0 base score
8.7High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.8% chance of exploitation in 30 days – higher than 56% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 2 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
browserstackbrowserstack-runnerAffected
  • <=0.9.5
Fixed in–
npmbrowserstack/browserstack-runnerpkg:npm/browserstack/browserstack-runnerOther threatsAffected
  • <=0.9.5
Fixed in–
GitHubbrowserstack-runnerpkg:github/browserstack-runnerOther threatsAffected
  • <=0.9.5
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Until an official fix is available, restrict network access to the BrowserStack Runner service to trusted users only and monitor for suspicious activity targeting the /_log endpoint. Avoid exposing this service to untrusted networks.

Description

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.

References

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