CVE-2026-39377

MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit probability: 0.0%, top 85% 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
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)
EPSS
18.1%
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 9× in last 7d / 38× 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. 2026-07-12 05:46 UTCEPSS rescore
  2. 2026-07-11 08:27 UTCEPSS rescore
  3. 2026-07-09 19:10 UTCEPSS rescore
  4. 2026-07-08 15:15 UTCEPSS rescore
  5. 2026-07-07 13:46 UTCEPSS rescore
  6. 2026-07-06 16:27 UTCEPSS rescore
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  8. 2026-07-06 02:23 UTCEPSS rescore
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  10. 2026-07-05 02:30 UTCEPSS rescore
  11. 2026-07-04 06:31 UTCEPSS rescore
  12. 2026-07-01 15:06 UTCEPSS rescore
  13. 2026-06-30 23:22 UTCEPSS rescore
  14. 2026-06-29 14:06 UTCEPSS rescore
  15. 2026-06-28 14:07 UTCEPSS rescore
  16. 2026-06-28 04:56 UTCEPSS rescore
  17. 2026-06-27 03:08 UTCEPSS rescore
  18. 2026-06-25 13:49 UTCEPSS rescore
  19. 2026-06-25 13:49 UTCEPSS rescore
  20. 2026-06-24 14:05 UTCEPSS rescore
  21. 2026-06-23 21:33 UTCEPSS rescore
  22. 2026-06-22 14:25 UTCEPSS rescore
  23. 2026-06-22 14:25 UTCEPSS rescore
  24. 2026-06-21 14:56 UTCEPSS rescore
  25. 2026-06-21 14:56 UTCEPSS rescore
Show 66 more
  1. 2026-06-21 01:59 UTCEPSS rescore
  2. 2026-06-19 19:25 UTCEPSS rescore
  3. 2026-06-19 19:25 UTCEPSS rescore
  4. 2026-06-18 17:52 UTCEPSS rescore
  5. 2026-06-18 17:52 UTCEPSS rescore
  6. 2026-06-17 17:53 UTCEPSS rescore
  7. 2026-06-16 17:52 UTCEPSS rescore
  8. 2026-06-15 17:49 UTCEPSS rescore
  9. 2026-06-14 23:18 UTCEPSS rescore
  10. 2026-06-14 18:46 UTCEG score recompute
  11. 2026-06-13 23:00 UTCEPSS rescore
  12. 2026-06-12 23:12 UTCEPSS rescore
  13. 2026-06-12 23:12 UTCEPSS rescore
  14. 2026-06-11 17:58 UTCEG score recompute
  15. 2026-06-11 14:00 UTCEPSS rescore
  16. 2026-06-10 22:18 UTCEPSS rescore
  17. 2026-06-10 13:22 UTCEPSS rescore
  18. 2026-06-10 06:29 UTCEG score recompute
  19. 2026-06-09 05:55 UTCEG score recompute
  20. 2026-06-08 14:17 UTCEPSS rescore
  21. 2026-06-08 14:17 UTCEPSS rescore
  22. 2026-06-08 05:18 UTCEG score recompute
  23. 2026-06-07 15:25 UTCEPSS rescore
  24. 2026-06-07 15:25 UTCEPSS rescore
  25. 2026-06-07 15:25 UTCEPSS rescore
  26. 2026-06-07 04:43 UTCEG score recompute
  27. 2026-06-07 04:43 UTCEG score recompute
  28. 2026-06-06 13:47 UTCEPSS rescore
  29. 2026-06-06 13:47 UTCEPSS rescore
  30. 2026-06-05 22:47 UTCEPSS rescore
  31. 2026-06-05 22:47 UTCEPSS rescore
  32. 2026-06-05 21:32 UTCEG score recompute
  33. 2026-06-05 06:10 UTCEPSS rescore
  34. 2026-06-05 06:10 UTCEPSS rescore
  35. 2026-06-04 18:30 UTCEG score recompute
  36. 2026-06-04 13:12 UTCEPSS rescore
  37. 2026-06-04 13:12 UTCEPSS rescore
  38. 2026-06-03 17:55 UTCEG score recompute
  39. 2026-06-02 20:13 UTCEPSS rescore
  40. 2026-06-02 17:02 UTCEG score recompute
  41. 2026-06-01 16:22 UTCEG score recompute
  42. 2026-06-01 13:52 UTCEPSS rescore
  43. 2026-06-01 13:52 UTCEPSS rescore
  44. 2026-06-01 13:51 UTCEPSS rescore
  45. 2026-05-31 22:30 UTCEPSS rescore
  46. 2026-05-31 22:30 UTCEPSS rescore
  47. 2026-05-31 00:16 UTCEPSS rescore
  48. 2026-05-31 00:16 UTCEPSS rescore
  49. 2026-05-31 00:16 UTCEPSS rescore
  50. 2026-05-29 13:44 UTCEPSS rescore
  51. 2026-05-29 13:44 UTCEPSS rescore
  52. 2026-05-28 13:44 UTCEPSS rescore
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  54. 2026-05-28 13:44 UTCEPSS rescore
  55. 2026-05-27 13:40 UTCEPSS rescore
  56. 2026-05-27 13:40 UTCEPSS rescore
  57. 2026-05-27 13:40 UTCEPSS rescore
  58. 2026-05-26 13:44 UTCEPSS rescore
  59. 2026-05-26 07:18 UTCEPSS rescore
  60. 2026-05-26 07:18 UTCEPSS rescore
  61. 2026-05-23 00:08 UTCEG score recompute
  62. 2026-05-20 22:38 UTCEPSS rescore
  63. 2026-05-20 22:38 UTCEPSS rescore
  64. 2026-05-20 16:37 UTCEG score recompute
  65. 2026-05-20 11:22 UTCEPSS rescore
  66. 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 18.1% 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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