CVE-2026-49143Public exploit

Unauthenticated code execution via /_log sandbox escape

Published Jun 2, 2026 · Updated Jun 2, 2026

Code injection in BrowserStack Runner 0.9.5 and earlier allows remote attackers on the local network to execute arbitrary host commands. The /_log handler maps JSON arguments through eval() inside vm.runInNewContext(), while util.format exposes a host Function constructor that escapes the sandbox. The test server listens on all interfaces without authentication during a test run, granting the attacker the runner process privileges and access to its data.

CVSS severity8.7
High
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in BrowserStack Runner 0.9.5 and earlier allows remote attackers on the local network to execute arbitrary host commands. The /_log handler maps JSON arguments through eval() inside vm.runInNewContext(), while util.format exposes a host Function constructor that escapes the sandbox. The test server listens on all interfaces without authentication during a test run, granting the attacker the runner process privileges and access to its data.

The record

CVE
CVE-2026-49143
Published
Jun 2, 2026
Updated
Jun 2, 2026
Vendor
BrowserStack
Product
BrowserStack Runner
Classifications
CWE-94, T1059
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 2, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=0.9.5

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

BrowserStack · BrowserStack Runnerversion=0 <=0.9.5

Published CVSS scores

8.8GitHubCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.7VulnCheckCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
T1059Command and Scripting Interpreter

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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