CVE-2026-49143

HIGHPre-NVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-06-03. a secondary CVSS source baseline 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Elevated
8.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
8.8
EG Score
8.8(medium)
EG Risk
56(Track*)
EG Risk 56/100SSVC: Track*

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity88% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS
31.7%
KEV
Not listed

Published

June 2, 2026

Last Modified

July 22, 2026

Advisory Details (2)

Auto-updated Jun 3, 2026
🔬 Proof of concept available. Patch available. Sources: github.
generic

BrowserStack Runner 0.9.5 Unauthenticated RCE via /_log HTTP Handler | Advisories | VulnCheck

https://www.vulncheck.com/advisories/browserstack-runner-unauthenticated-rce-via-log-http-handler
github Patch Available🟡 PoC Available

Remote Code Execution via vm sandbox escape in _log HTTP handler · Advisory · browserstack/browserstack-runner · GitHub

https://github.com/browserstack/browserstack-runner/security/advisories/GHSA-6vr3-7wcx-v5g5

Vendor Advisories for CVE-2026-49143(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
npmbrowserstack-runner—ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
browserstack-runner———

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 60× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 126 total refreshes for this CVE.

  1. 2026-07-23 03:18 UTCEG score recompute
  2. 2026-07-22 14:08 UTCEPSS rescore
  3. 2026-07-21 15:25 UTCEPSS rescore
  4. 2026-07-20 17:08 UTCEPSS rescore
  5. 2026-07-19 14:31 UTCEPSS rescore
  6. 2026-07-19 14:31 UTCEPSS rescore
  7. 2026-07-19 02:29 UTCEPSS rescore
  8. 2026-07-18 10:04 UTCEPSS rescore
  9. 2026-07-16 17:03 UTCEPSS rescore
  10. 2026-07-16 00:54 UTCGHSA enrichment
  11. 2026-07-15 16:57 UTCEPSS rescore
  12. 2026-07-15 02:00 UTCEPSS rescore
  13. 2026-07-14 16:39 UTCGHSA enrichment
  14. 2026-07-14 03:36 UTCGHSA enrichment
  15. 2026-07-13 22:30 UTCEPSS rescore
  16. 2026-07-13 06:13 UTCEPSS rescore
  17. 2026-07-12 05:46 UTCEPSS rescore
  18. 2026-07-12 00:40 UTCGHSA enrichment
  19. 2026-07-11 12:51 UTCGHSA enrichment
  20. 2026-07-11 08:27 UTCEPSS rescore
  21. 2026-07-09 19:10 UTCEPSS rescore
  22. 2026-07-09 07:23 UTCGHSA enrichment
  23. 2026-07-08 16:34 UTCGHSA enrichment
  24. 2026-07-08 15:16 UTCEPSS rescore
  25. 2026-07-07 13:46 UTCEPSS rescore
Show 75 more
  1. 2026-07-06 16:27 UTCEPSS rescore
  2. 2026-07-06 02:23 UTCEPSS rescore
  3. 2026-07-05 02:30 UTCEPSS rescore
  4. 2026-07-04 06:31 UTCEPSS rescore
  5. 2026-07-03 20:39 UTCGHSA enrichment
  6. 2026-07-03 00:25 UTCGHSA enrichment
  7. 2026-07-02 12:40 UTCGHSA enrichment
  8. 2026-07-01 23:32 UTCGHSA enrichment
  9. 2026-07-01 15:07 UTCEPSS rescore
  10. 2026-07-01 10:08 UTCGHSA enrichment
  11. 2026-06-30 23:22 UTCEPSS rescore
  12. 2026-06-30 22:23 UTCGHSA enrichment
  13. 2026-06-30 01:47 UTCGHSA enrichment
  14. 2026-06-29 14:06 UTCEPSS rescore
  15. 2026-06-29 14:06 UTCEPSS rescore
  16. 2026-06-29 14:02 UTCGHSA enrichment
  17. 2026-06-29 02:18 UTCGHSA enrichment
  18. 2026-06-28 14:31 UTCGHSA enrichment
  19. 2026-06-28 14:07 UTCEPSS rescore
  20. 2026-06-28 04:56 UTCEPSS rescore
  21. 2026-06-28 04:56 UTCEPSS rescore
  22. 2026-06-28 02:37 UTCGHSA enrichment
  23. 2026-06-27 14:52 UTCGHSA enrichment
  24. 2026-06-27 03:08 UTCEPSS rescore
  25. 2026-06-27 03:06 UTCGHSA enrichment
  26. 2026-06-26 15:21 UTCGHSA enrichment
  27. 2026-06-26 01:52 UTCGHSA enrichment
  28. 2026-06-25 14:07 UTCGHSA enrichment
  29. 2026-06-25 13:49 UTCEPSS rescore
  30. 2026-06-25 02:19 UTCGHSA enrichment
  31. 2026-06-24 14:33 UTCGHSA enrichment
  32. 2026-06-24 14:05 UTCEPSS rescore
  33. 2026-06-23 21:33 UTCEPSS rescore
  34. 2026-06-23 21:33 UTCEPSS rescore
  35. 2026-06-23 19:27 UTCGHSA enrichment
  36. 2026-06-22 14:25 UTCEPSS rescore
  37. 2026-06-22 14:25 UTCEPSS rescore
  38. 2026-06-21 14:56 UTCEPSS rescore
  39. 2026-06-21 14:56 UTCEPSS rescore
  40. 2026-06-21 01:59 UTCEPSS rescore
  41. 2026-06-21 01:59 UTCEPSS rescore
  42. 2026-06-20 12:57 UTCGHSA enrichment
  43. 2026-06-19 23:58 UTCGHSA enrichment
  44. 2026-06-19 19:26 UTCEPSS rescore
  45. 2026-06-19 19:26 UTCEPSS rescore
  46. 2026-06-18 17:52 UTCEPSS rescore
  47. 2026-06-18 17:52 UTCEPSS rescore
  48. 2026-06-18 16:39 UTCGHSA enrichment
  49. 2026-06-18 02:28 UTCGHSA enrichment
  50. 2026-06-17 17:53 UTCEPSS rescore
  51. 2026-06-17 14:44 UTCGHSA enrichment
  52. 2026-06-17 02:58 UTCGHSA enrichment
  53. 2026-06-16 17:53 UTCEPSS rescore
  54. 2026-06-16 15:13 UTCGHSA enrichment
  55. 2026-06-16 03:28 UTCGHSA enrichment
  56. 2026-06-15 17:49 UTCEPSS rescore
  57. 2026-06-15 17:49 UTCEPSS rescore
  58. 2026-06-15 15:41 UTCGHSA enrichment
  59. 2026-06-15 03:56 UTCGHSA enrichment
  60. 2026-06-14 23:18 UTCEPSS rescore
  61. 2026-06-14 16:10 UTCGHSA enrichment
  62. 2026-06-14 04:22 UTCGHSA enrichment
  63. 2026-06-13 23:00 UTCEPSS rescore
  64. 2026-06-13 16:08 UTCGHSA enrichment
  65. 2026-06-13 03:48 UTCGHSA enrichment
  66. 2026-06-12 23:12 UTCEPSS rescore
  67. 2026-06-12 23:12 UTCEPSS rescore
  68. 2026-06-12 16:03 UTCGHSA enrichment
  69. 2026-06-12 04:18 UTCGHSA enrichment
  70. 2026-06-11 16:33 UTCGHSA enrichment
  71. 2026-06-11 14:00 UTCEPSS rescore
  72. 2026-06-11 04:49 UTCGHSA enrichment
  73. 2026-06-10 22:19 UTCEPSS rescore
  74. 2026-06-10 17:05 UTCGHSA enrichment
  75. 2026-06-10 13:22 UTCEPSS rescore

Related CVEs(same product + same CWE)

Same product

1 shown

npm:browserstack-runner

Frequently asked(5)

What is CVE-2026-49143?
CVE-2026-49143 is a high vulnerability published on June 2, 2026. 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…
When was CVE-2026-49143 disclosed?
CVE-2026-49143 was first published in the National Vulnerability Database on June 2, 2026, with the most recent update on July 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-49143 actively exploited?
CVE-2026-49143 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 31.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-49143?
CVE-2026-49143 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2026-49143?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-49143, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-49143

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