CVE-2026-40171

HIGHNVD 8.48.4—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.4 under NVD CVSS v3. EPSS exploit probability: 0.5%, top 61% 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
Trending — 3 sources updated this week
8.4EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.4Exploit: None knownExposed: 0

A fix is available — apply it.

In Jupyter Notebook versions 7.0.0 through 7.5.5, JupyterLab versions 4.5.6 and earlier, and the corresponding @jupyter-notebook/help-extension and @jupyterlab/help-extension packages before 7.5.6 and 4.5.7, a stored cross-site scripting issue in the help command linker can be chained with attacker-controlled notebook content to steal authentication tokens with a single click.

An attacker can craft a malicious notebook file containing elements that appear indistinguishable from legitimate controls and trigger execution when a user interacts with them. Successful exploitation allows theft of the user's authentication token and complete takeover of the Jupyter session through the REST API, including reading files, creating or modifying files, accessing kernels to execute arbitrary code, and creating terminals for shell access. This issue has been fixed in Notebook 7.5.6, JupyterLab 4.5.7, @jupyter-notebook/help-extension 7.5.6, and @jupyterlab/help-extension 4.5.7. As a workaround, disable the affected help extensions or set allowCommandLinker to false in the sanitizer configuration.

CVSS v3
8.4
EG Score
8.4(medium)
EG Risk
38(Track)
EG Risk 38/100SSVC: 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
Severity84% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
39%
KEV
Not listed

Published

May 6, 2026

Last Modified

May 7, 2026

Advisory Details (1)

Auto-updated May 6, 2026
Patch available. Sources: github.
github Patch Available

Command linker attributes chained with help command enable one-click authentication token theft · Advisory · jupyter/notebook · GitHub

https://github.com/jupyter/notebook/security/advisories/GHSA-rch3-82jr-f9w9

Vendor Advisories for CVE-2026-40171(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
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

(7 across 4 ecosystems)
Debian:14(2)
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—
jupyter-notebook6.4.13-5, 7.0.0-1, 7.0.0-2——
npm(2)
PackageVulnerable rangeFixed inDependents
@jupyterlab/help-extension—4.5.7—
@jupyter-notebook/help-extension—7.5.6—
PyPI(2)
PackageVulnerable rangeFixed inDependents
jupyterlab0.0.1 ... 4.5.6 (584 versions)4.5.7—
notebook7.0.0 ... 7.5.5 (69 versions)7.5.6—
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)——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 63× 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 162 total refreshes for this CVE.

  1. 2026-08-25 13:49 UTCEPSS rescore
  2. 2026-08-23 19:43 UTCEG score recompute
  3. 2026-08-23 19:43 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. 2026-08-19 17:03 UTCEPSS rescore
  8. 2026-08-18 13:48 UTCEPSS rescore
  9. 2026-08-17 13:47 UTCEPSS rescore
  10. 2026-08-17 12:50 UTCEG score recompute
  11. 2026-08-17 12:50 UTCVendor advisory
  12. 2026-08-16 14:56 UTCEPSS rescore
  13. 2026-08-16 04:48 UTCEG score recompute
  14. 2026-08-16 04:48 UTCVendor advisory
  15. 2026-08-16 02:14 UTCEPSS rescore
  16. 2026-08-15 01:50 UTCEG score recompute
  17. 2026-08-15 01:50 UTCVendor advisory
  18. 2026-08-15 01:30 UTCEPSS rescore
  19. 2026-08-14 14:36 UTCVendor advisory
  20. 2026-08-14 03:21 UTCEG score recompute
  21. 2026-08-14 03:21 UTCVendor advisory
  22. 2026-08-13 22:00 UTCEPSS rescore
  23. 2026-08-13 04:10 UTCVendor advisory
  24. 2026-08-12 16:56 UTCEG score recompute
  25. 2026-08-12 16:56 UTCVendor advisory
Show 75 more
  1. 2026-08-12 13:51 UTCEPSS rescore
  2. 2026-08-11 15:58 UTCEG score recompute
  3. 2026-08-11 15:58 UTCVendor advisory
  4. 2026-08-11 13:43 UTCEPSS rescore
  5. 2026-08-11 01:28 UTCEG score recompute
  6. 2026-08-11 01:28 UTCVendor advisory
  7. 2026-08-11 00:00 UTCEPSS rescore
  8. 2026-08-10 12:14 UTCVendor advisory
  9. 2026-08-10 01:00 UTCEG score recompute
  10. 2026-08-10 01:00 UTCVendor advisory
  11. 2026-08-09 13:46 UTCEPSS rescore
  12. 2026-08-09 13:46 UTCVendor advisory
  13. 2026-08-09 02:31 UTCVendor advisory
  14. 2026-08-08 09:00 UTCVendor advisory
  15. 2026-08-07 21:46 UTCEG score recompute
  16. 2026-08-07 21:46 UTCVendor advisory
  17. 2026-08-07 10:32 UTCVendor advisory
  18. 2026-08-06 20:44 UTCEG score recompute
  19. 2026-08-06 20:44 UTCVendor advisory
  20. 2026-08-06 13:46 UTCEPSS rescore
  21. 2026-08-06 09:30 UTCVendor advisory
  22. 2026-08-05 22:16 UTCEG score recompute
  23. 2026-08-05 22:16 UTCVendor advisory
  24. 2026-08-05 19:17 UTCEPSS rescore
  25. 2026-08-04 15:10 UTCEPSS rescore
  26. 2026-08-04 10:38 UTCEPSS rescore
  27. 2026-08-03 19:45 UTCEG score recompute
  28. 2026-08-03 19:45 UTCVendor advisory
  29. 2026-08-03 10:36 UTCEPSS rescore
  30. 2026-08-03 03:45 UTCVendor advisory
  31. 2026-08-02 15:58 UTCVendor advisory
  32. 2026-08-02 04:43 UTCEG score recompute
  33. 2026-08-02 04:43 UTCVendor advisory
  34. 2026-08-02 02:27 UTCEPSS rescore
  35. 2026-08-01 04:16 UTCEPSS rescore
  36. 2026-07-30 16:28 UTCEPSS rescore
  37. 2026-07-30 01:30 UTCEPSS rescore
  38. 2026-07-27 14:13 UTCEPSS rescore
  39. 2026-07-26 14:54 UTCEPSS rescore
  40. 2026-07-26 14:54 UTCEPSS rescore
  41. 2026-07-25 14:18 UTCEPSS rescore
  42. 2026-07-25 14:18 UTCEPSS rescore
  43. 2026-07-24 14:17 UTCEPSS rescore
  44. 2026-07-24 14:17 UTCEPSS rescore
  45. 2026-07-23 14:18 UTCEPSS rescore
  46. 2026-07-23 14:18 UTCEPSS rescore
  47. 2026-07-23 03:11 UTCEG score recompute
  48. 2026-07-22 14:08 UTCEPSS rescore
  49. 2026-07-21 15:24 UTCEPSS rescore
  50. 2026-07-20 17:08 UTCEPSS rescore
  51. 2026-07-19 14:31 UTCEPSS rescore
  52. 2026-07-19 02:29 UTCEPSS rescore
  53. 2026-07-18 10:04 UTCEPSS rescore
  54. 2026-07-16 17:03 UTCEPSS rescore
  55. 2026-07-15 16:57 UTCEPSS rescore
  56. 2026-07-15 16:57 UTCEPSS rescore
  57. 2026-07-15 14:19 UTCOSV refresh
  58. 2026-07-15 02:00 UTCEPSS rescore
  59. 2026-07-13 22:30 UTCEPSS rescore
  60. 2026-07-13 06:13 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-2026-40171?
CVE-2026-40171 is a high vulnerability published on May 6, 2026. In Jupyter Notebook versions 7.0.0 through 7.5.5, JupyterLab versions 4.5.6 and earlier, and the corresponding @jupyter-notebook/help-extension and @jupyterlab/help-extension packages before 7.5.6 and 4.5.7, a stored cross-site scripting issue in the help command linker can be chained with…
When was CVE-2026-40171 disclosed?
CVE-2026-40171 was first published in the National Vulnerability Database on May 6, 2026, with the most recent update on May 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-40171 actively exploited?
CVE-2026-40171 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 61.0% of all scored CVEs.
What is the CVSS score of CVE-2026-40171?
CVE-2026-40171 has a CVSS v3 base score of 8.4 (NVD).
How do I remediate CVE-2026-40171?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-40171, 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-2026-40171

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