CVE-2026-42266

HIGHPre-NVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.6%, top 56% 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, secondary
Trending — 3 sources updated this week
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 8.8Exploit: None knownExposed: 0

A fix is available — apply it.

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)
EG Risk
40(Track)
EG Risk 40/100SSVC: 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%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
44%
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.

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatmta/mta-solution-server-rhel9:17841098832026-07-21redhat

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

(3 across 3 ecosystems)
Debian:13(1)
PackageVulnerable rangeFixed inDependents
jupyterlab4.0.11+ds1+~cs11.25.27-7 ... 4.4.8+ds1+~3.1.0+~0.16.6+~cs1.4.4-1 (26 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
jupyterlab4.0.11+ds1+~cs11.25.27-7 ... 4.4.8+ds1+~3.1.0+~0.16.6+~cs1.4.4-1 (25 versions)4.4.10+ds1+~3.1.0+~0.16.6+~cs1.4.4-3—
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 9× in last 7d / 68× 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 159 total refreshes for this CVE.

  1. 2026-08-25 13:49 UTCEPSS rescore
  2. 2026-08-23 17:54 UTCEG score recompute
  3. 2026-08-23 17:54 UTCVendor advisory
  4. 2026-08-23 00:19 UTCEPSS rescore
  5. 2026-08-21 23:49 UTCEPSS rescore
  6. 2026-08-20 22:55 UTCEPSS rescore
  7. 2026-08-20 21:29 UTCEG score recompute
  8. 2026-08-20 21:29 UTCVendor advisory
  9. 2026-08-19 17:03 UTCEPSS rescore
  10. 2026-08-18 13:48 UTCEPSS rescore
  11. 2026-08-17 13:47 UTCEPSS rescore
  12. 2026-08-17 10:41 UTCEG score recompute
  13. 2026-08-17 10:41 UTCVendor advisory
  14. 2026-08-16 14:56 UTCEPSS rescore
  15. 2026-08-16 04:05 UTCEG score recompute
  16. 2026-08-16 04:05 UTCVendor advisory
  17. 2026-08-16 02:14 UTCEPSS rescore
  18. 2026-08-15 01:30 UTCEPSS rescore
  19. 2026-08-15 00:37 UTCVendor advisory
  20. 2026-08-14 13:35 UTCVendor advisory
  21. 2026-08-14 02:34 UTCEG score recompute
  22. 2026-08-14 02:34 UTCVendor advisory
  23. 2026-08-13 22:00 UTCEPSS rescore
  24. 2026-08-13 02:54 UTCVendor advisory
  25. 2026-08-12 15:52 UTCEG score recompute
Show 75 more
  1. 2026-08-12 15:52 UTCVendor advisory
  2. 2026-08-12 13:51 UTCEPSS rescore
  3. 2026-08-11 15:29 UTCEG score recompute
  4. 2026-08-11 15:29 UTCVendor advisory
  5. 2026-08-11 13:43 UTCEPSS rescore
  6. 2026-08-11 00:58 UTCEG score recompute
  7. 2026-08-11 00:58 UTCVendor advisory
  8. 2026-08-11 00:00 UTCEPSS rescore
  9. 2026-08-10 11:30 UTCVendor advisory
  10. 2026-08-09 23:59 UTCEG score recompute
  11. 2026-08-09 23:59 UTCVendor advisory
  12. 2026-08-09 13:46 UTCEPSS rescore
  13. 2026-08-09 12:58 UTCVendor advisory
  14. 2026-08-09 01:56 UTCEG score recompute
  15. 2026-08-09 01:56 UTCVendor advisory
  16. 2026-08-08 16:37 UTCEPSS rescore
  17. 2026-08-08 05:10 UTCVendor advisory
  18. 2026-08-07 18:08 UTCEG score recompute
  19. 2026-08-07 18:08 UTCVendor advisory
  20. 2026-08-07 07:07 UTCVendor advisory
  21. 2026-08-06 19:45 UTCEG score recompute
  22. 2026-08-06 19:45 UTCVendor advisory
  23. 2026-08-06 13:46 UTCEPSS rescore
  24. 2026-08-06 08:44 UTCVendor advisory
  25. 2026-08-05 21:42 UTCEG score recompute
  26. 2026-08-05 21:42 UTCVendor advisory
  27. 2026-08-05 19:17 UTCEPSS rescore
  28. 2026-08-04 15:10 UTCEPSS rescore
  29. 2026-08-04 10:38 UTCEPSS rescore
  30. 2026-08-03 19:10 UTCEG score recompute
  31. 2026-08-03 19:10 UTCVendor advisory
  32. 2026-08-03 10:36 UTCEPSS rescore
  33. 2026-08-02 20:24 UTCVendor advisory
  34. 2026-08-02 09:23 UTCEG score recompute
  35. 2026-08-02 09:23 UTCVendor advisory
  36. 2026-08-02 02:27 UTCEPSS rescore
  37. 2026-08-01 20:06 UTCEG score recompute
  38. 2026-08-01 20:06 UTCVendor advisory
  39. 2026-08-01 04:16 UTCEPSS rescore
  40. 2026-07-30 16:28 UTCEPSS rescore
  41. 2026-07-30 01:30 UTCEPSS rescore
  42. 2026-07-28 15:36 UTCEPSS rescore
  43. 2026-07-27 14:13 UTCEPSS rescore
  44. 2026-07-26 14:54 UTCEPSS rescore
  45. 2026-07-26 14:54 UTCEPSS rescore
  46. 2026-07-25 14:18 UTCEPSS rescore
  47. 2026-07-24 14:17 UTCEPSS rescore
  48. 2026-07-23 14:18 UTCEPSS rescore
  49. 2026-07-23 03:11 UTCEG score recompute
  50. 2026-07-22 14:08 UTCEPSS rescore
  51. 2026-07-21 15:24 UTCEPSS rescore
  52. 2026-07-20 17:08 UTCEPSS rescore
  53. 2026-07-19 14:31 UTCEPSS rescore
  54. 2026-07-19 02:29 UTCEPSS rescore
  55. 2026-07-18 10:04 UTCEPSS rescore
  56. 2026-07-18 03:29 UTCOSV refresh
  57. 2026-07-16 17:03 UTCEPSS rescore
  58. 2026-07-15 16:57 UTCEPSS rescore
  59. 2026-07-15 02:00 UTCEPSS rescore
  60. 2026-07-13 22:30 UTCEPSS rescore
  61. 2026-07-13 06:13 UTCEPSS rescore
  62. 2026-07-12 05:46 UTCEPSS rescore
  63. 2026-07-11 08:27 UTCEPSS rescore
  64. 2026-07-09 19:10 UTCEPSS rescore
  65. 2026-07-08 15:15 UTCEPSS rescore
  66. 2026-07-07 13:46 UTCEPSS rescore
  67. 2026-07-06 16:27 UTCEPSS rescore
  68. 2026-07-06 16:27 UTCEPSS rescore
  69. 2026-07-06 02:23 UTCEPSS rescore
  70. 2026-07-06 02:23 UTCEPSS rescore
  71. 2026-07-05 02:30 UTCEPSS rescore
  72. 2026-07-04 06:31 UTCEPSS rescore
  73. 2026-07-01 15:06 UTCEPSS rescore
  74. 2026-06-30 23:22 UTCEPSS rescore
  75. 2026-06-29 14:06 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 1% probability of exploitation in the next 30 days, which ranks it in the top 56.2% of all scored CVEs.
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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