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
8.4EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 8.4Exploit: None knownExposed services: Not assessed

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
8.4HIGHmedium confidence
EG Risk
38
EG Risk 38/100

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%
EPSS PROB
0.7%
EPSS %ILE
50th
KEV
Not listed

Published

May 6, 2026

Last Modified

May 7, 2026

Advisory Details (1)

Auto-updated May 6, 2026
Patch available. Sources: github.
githubMentions a patch (unverified)

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(3)

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 / EcosystemFix (by version range) / 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 rangeFix by version rangeDependents
jupyterlab4.0.11+ds1+~cs11.25.27-7 ... 4.4.8+ds1+~3.1.0+~0.16.6+~cs1.4.4-1 (25 versions)
  • every version up to 4.4.10+ds1+~3.1.0+~0.16.6+~cs1.4.4-3: fixed in 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, 7.4.7-1, 7.4.7-2
  • every version up to 7.4.7-3: fixed in 7.4.7-3
—
npm(2)
PackageVulnerable rangeFix by version rangeDependents
@jupyterlab/help-extension—
  • every version up to 4.5.7: fixed in 4.5.7
—
@jupyter-notebook/help-extension—
  • 7.0.0 up to 7.5.6: fixed in 7.5.6
—
PyPI(2)
PackageVulnerable rangeFix by version rangeDependents
jupyterlab0.0.1 ... 4.5.6 (584 versions)
  • every version up to 4.5.7: fixed in 4.5.7
—
notebook7.0.0 ... 7.5.5 (69 versions)
  • 7.0.0 up to 7.5.6: fixed in 7.5.6
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
jupyterlab4.0.11+ds1+~cs11.25.27-7 ... 4.4.8+ds1+~3.1.0+~0.16.6+~cs1.4.4-1 (29 versions)
  • every version on: no fix on record
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 24× 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 199 total refreshes for this CVE.

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

Related CVEs(same product + same vendor + same CWE)

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 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 0.7% probability of exploitation in the next 30 days (50th percentile of EPSS-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?
A fix for CVE-2026-40171 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-40171 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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