CVE-2026-6658

MEDIUMPre-NVD 5.45.4—
EchelonGraph scoreMEDIUM confidence

Score 5.4 from GitHub Security Advisory published 2026-06-26. a secondary CVSS source baseline 5.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
5.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.4Exploit: None knownExposed: 0

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

A vulnerability in jupyter/nbconvert versions <= 7.17.0 allows for Cross-site Scripting (XSS) via unsanitized text/vnd.mermaid output in HTML exports. The data_mermaid block in share/templates/lab/base.html.j2 renders text/vnd.mermaid cell output directly into HTML without escaping, enabling attackers to inject arbitrary HTML/JavaScript by breaking out of the `` tag. This vulnerability impacts any server using nbconvert to render notebooks as HTML, allowing attackers to execute arbitrary JavaScript in the context of users viewing the HTML export.

CVSS v3
5.4
EG Score
5.4(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
Severity54% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
13%
KEV
Not listed

Published

June 26, 2026

Last Modified

June 26, 2026

Advisory Details (1)

Auto-updated Jun 26, 2026
No patch confirmed yet.
generic

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https://huntr.com/bounties/47570290-3b26-4477-8cfa-fdef7db5aefe

Vendor Advisories for CVE-2026-6658(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
nbconvert5.6.1-3 ... 7.17.1-2 (21 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
nbconvert6.5.3-3 ... 7.17.1-2 (10 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
nbconvert7.16.6-1, 7.16.6-1+deb13u1, 7.17.0-1, 7.17.1-1, 7.17.1-2——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
nbconvert7.16.6-1, 7.17.0-1, 7.17.1-1, 7.17.1-2——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 52× 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 163 total refreshes for this CVE.

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

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-6658?
CVE-2026-6658 is a medium vulnerability published on June 26, 2026. A vulnerability in jupyter/nbconvert versions <= 7.17.0 allows for Cross-site Scripting (XSS) via unsanitized text/vnd.mermaid output in HTML exports. The data_mermaid block in share/templates/lab/base.html.j2 renders text/vnd.mermaid cell output directly into HTML without escaping, enabling…
When was CVE-2026-6658 disclosed?
CVE-2026-6658 was first published in the National Vulnerability Database on June 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-6658 actively exploited?
CVE-2026-6658 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 86.6% of all scored CVEs.
What is the CVSS score of CVE-2026-6658?
CVE-2026-6658 has a CVSS v3 base score of 5.4 (NVD).
How do I remediate CVE-2026-6658?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-6658, 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

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