CVE-2026-39377

MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 82% 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
6.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.5Exploit: NoneExposed: 0

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

The nbconvert tool, jupyter nbconvert, converts Jupyter notebooks to various other formats via Jinja templates. Versions 6.5 through 7.17.0 allow arbitrary file writes to locations outside the intended output directory when processing notebooks containing crafted cell attachment filenames. The ExtractAttachmentsPreprocessor passes attachment filenames directly to the filesystem without sanitization, enabling path traversal attacks. This vulnerability provides complete control over both the destination path and file extension. Version 7.17.1 contains a patch.

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: 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
Severity65% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
18.3%
KEV
Not listed

Published

April 21, 2026

Last Modified

April 23, 2026

Advisory Details (2)

Auto-updated Jun 14, 2026
Patch available. Sources: github_release, github.
github Patch Available

Arbitrary File Write via Path Traversal in Cell Attachment Filenames · Advisory · jupyter/nbconvert · GitHub

https://github.com/jupyter/nbconvert/security/advisories/GHSA-4c99-qj7h-p3vg
github_release Patch Available

v7.17.1

Patch available: jupyter/nbconvert v7.17.1

https://github.com/jupyter/nbconvert/releases/tag/v7.17.1

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
nbconvert6.5.0 ... 7.9.2 (53 versions)7.17.1—

Weakness Classification(2)

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

Data Freshness Timeline

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

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-39377?
CVE-2026-39377 is a medium vulnerability published on April 21, 2026. The nbconvert tool, jupyter nbconvert, converts Jupyter notebooks to various other formats via Jinja templates. Versions 6.5 through 7.17.0 allow arbitrary file writes to locations outside the intended output directory when processing notebooks containing crafted cell attachment filenames. The…
When was CVE-2026-39377 disclosed?
CVE-2026-39377 was first published in the National Vulnerability Database on April 21, 2026, with the most recent update on April 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-39377 actively exploited?
CVE-2026-39377 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 18.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-39377?
CVE-2026-39377 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-39377?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-39377, 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.

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