CVE-2021-41134

HIGHNVD 8.78.7—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.7 under NVD CVSS v3. EPSS exploit probability: 0.7% (51st percentile of EPSS-scored CVEs). 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
8.7EG
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: 8.7Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

nbdime provides tools for diffing and merging of Jupyter Notebooks. In affected versions a stored cross-site scripting (XSS) issue exists within the Jupyter-owned nbdime project. It appears that when reading the file name and path from disk, the extension does not sanitize the string it constructs before returning it to be displayed. The diffNotebookCheckpoint function within nbdime causes this issue. When attempting to display the name of the local notebook (diffNotebookCheckpoint), nbdime appears to simply append .ipynb to the name of the input file. The NbdimeWidget is then created, and the base string is passed through to the request API function. From there, the frontend simply renders the HTML tag and anything along with it. Users are advised to patch to the most recent version of the affected product.

CVSS v3
8.7
EG Score
8.7HIGHmedium confidence
EG Risk
44
EG Risk 44/100CISA SSVC

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
Severity87% × 45%
Exploitation1% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track or Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.7%
EPSS %ILE
51st
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track or Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

November 3, 2021

Last Modified

November 21, 2024

Advisory Details (2)

Auto-updated Sep 1, 2026
Patch available. Sources: github_commit, github.
githubMentions a patch (unverified)

Stored XSS in Jupyter nbdime · Advisory · jupyter/nbdime · GitHub

Affected: v. 1.1.1

https://github.com/jupyter/nbdime/security/advisories/GHSA-p6rw-44q7-3fw4
github_commit Patch Available

commit e44a5cc7677f (jupyter/nbdime)

Patch available: jupyter/nbdime 3.1.1 (contains commit e44a5cc7677f)

https://github.com/jupyter/nbdime/commit/e44a5cc7677f24b45ebafc756db49058c2f750ea

Affected Packages

(3 across 2 ecosystems)
npm(2)
PackageVulnerable rangeFix by version rangeDependents
nbdime—
  • every version up to 5.0.2: fixed in 5.0.2
  • 6.0.0 up to 6.1.2: fixed in 6.1.2
—
nbdime-jupyterlab—
  • every version up to 1.0.1: fixed in 1.0.1
  • 2.0.0 up to 2.1.1: fixed in 2.1.1
—
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
nbdime0.1.0 ... 3.1.0 (24 versions)
  • every version up to 1.1.1: fixed in 1.1.1
  • 2.0.0 up to 2.1.1: fixed in 2.1.1
  • 3.0.0 up to 3.1.1: fixed in 3.1.1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 31× 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 184 total refreshes for this CVE.

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

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Frequently asked(5)

What is CVE-2021-41134?
CVE-2021-41134 is a high vulnerability published on November 3, 2021. nbdime provides tools for diffing and merging of Jupyter Notebooks. In affected versions a stored cross-site scripting (XSS) issue exists within the Jupyter-owned nbdime project. It appears that when reading the file name and path from disk, the extension does not sanitize the string it constructs…
When was CVE-2021-41134 disclosed?
CVE-2021-41134 was first published on November 3, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-41134 actively exploited?
CVE-2021-41134 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (51st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-41134?
CVE-2021-41134 has a CVSS v3 base score of 8.7 (NVD).
How do I remediate CVE-2021-41134?
A fix for CVE-2021-41134 is available: update to the fixed version the vendor names in its advisory.

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