CVE-2026-49143

HIGHPre-NVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-06-03. the CNA's CVSS baseline 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:vulncheck, epss, ghsa
Trending — 4 sources updated this weekElevated
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.8Exploit: Elevated riskExposed: 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 PROB
0%
EPSS %ILE
33%
KEV
Not listed

Published

June 2, 2026

Last Modified

August 14, 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 7× in last 7d / 37× 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 241 total refreshes for this CVE.

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

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Same product

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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 August 14, 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 0% probability of exploitation in the next 30 days, which ranks it in the top 67.2% of all scored CVEs.
What is the CVSS score of CVE-2026-49143?
CVE-2026-49143 has a CVSS v4.0 base score of 8.8 (CNA self-assessment; NVD's own analysis pending).
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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