CVE-2026-42266

HIGHPre-NVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.8 under NVD CVSS v3. EPSS exploit probability: 0.5%, top 62% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
8.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 8.8Exploit: NoneExposed: 0

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

JupyterLab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. From 4.0.0 to 4.5.6, the allow-list of extensions that can be installed from PyPI Extension Manager (allowed_extensions_uris) is not correctly enforced by JupyterLab. The PyPI Extension Manager was not contained to packages listed on the default PyPI index. This vulnerability is fixed in 4.5.7.

CVSS v3
8.8
EG Score
8.8(medium)
EPSS
41.6%
KEV
Not listed

Published

May 13, 2026

Last Modified

July 22, 2026

Advisory Details (1)

Auto-updated May 13, 2026
Patch available. Sources: github.
github Patch Available

Allowlist for PyPI Extension Manager not correctly enforced, PyPI Extension Manager not limited to default PyPI index · Advisory · jupyterlab/jupyterlab · GitHub

https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-37w4-hwhx-4rc4

Vendor Advisories for CVE-2026-42266(2)

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

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
jupyterlab4.0.0 ... 4.5.6 (102 versions)4.5.7—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 33× 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.

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

Frequently asked(5)

What is CVE-2026-42266?
CVE-2026-42266 is a high vulnerability published on May 13, 2026. JupyterLab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. From 4.0.0 to 4.5.6, the allow-list of extensions that can be installed from PyPI Extension Manager (allowedextensionsuris) is not correctly enforced by JupyterLab. The…
When was CVE-2026-42266 disclosed?
CVE-2026-42266 was first published in the National Vulnerability Database on May 13, 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-2026-42266 actively exploited?
CVE-2026-42266 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 41.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-42266?
CVE-2026-42266 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2026-42266?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42266, 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

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