CVE-2026-59930

MEDIUMPre-NVD 4.34.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 91% 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, secondary
Elevated
4.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.3Exploit: Elevated riskExposed: 0

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

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, the toc plugin and TableOfContents directive generate heading IDs as predictable toc_N values without slugifying the heading text, allowing attacker-controlled id="toc_N" content to collide with generated anchors and redirect same-page navigation, CSS selectors, or JavaScript handlers. This issue is fixed in version 3.3.0.

CVSS v3
4.3
EG Score
4.3(medium)
EG Risk
35(Track)
EG Risk 35/100SSVC: 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
Severity43% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
9%
KEV
Not listed

Published

July 8, 2026

Last Modified

July 9, 2026

Advisory Details (3)

Auto-updated Jul 9, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_release, github.
github_release Patch Available

v3.3.0

Patch available: lepture/mistune v3.3.0

https://github.com/lepture/mistune/releases/tag/v3.3.0
github_commit Patch Available

commit c4093c4742ed (lepture/mistune)

Patch available: lepture/mistune v3.3.0 (contains commit c4093c4742ed)

https://github.com/lepture/mistune/commit/c4093c4742ed0d10d9332fb8edb455869b7b581b
github Patch Available🟡 PoC Available

toc / TableOfContents directive: heading IDs use predictable `toc_N` numbering with no slugification, allowing collision with attacker-controlled `id="toc_N"` content · Advisory · lepture/mistune · GitHub

https://github.com/lepture/mistune/security/advisories/GHSA-2hm2-hc3v-44h9

Vendor Advisories for CVE-2026-59930(2)

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:12(1)
PackageVulnerable rangeFixed inDependents
mistune2.0.4-1 ... 3.1.4-1 (6 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
mistune3.1.3-1, 3.1.4-1——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
mistune3.1.3-1, 3.1.4-1——
PyPI(1)
PackageVulnerable rangeFixed inDependents
mistune0.1.0 ... 3.2.1 (51 versions)3.3.0—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 11× in last 7d / 55× 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. 2026-08-26 08:24 UTCEG score recompute
  2. 2026-08-25 13:49 UTCEPSS rescore
  3. 2026-08-24 22:19 UTCEG score recompute
  4. 2026-08-23 23:05 UTCEG score recompute
  5. 2026-08-23 00:19 UTCEPSS rescore
  6. 2026-08-22 00:27 UTCEG score recompute
  7. 2026-08-21 23:49 UTCEPSS rescore
  8. 2026-08-21 01:13 UTCEG score recompute
  9. 2026-08-20 22:55 UTCEPSS rescore
  10. 2026-08-20 01:59 UTCEG score recompute
  11. 2026-08-19 17:04 UTCEPSS rescore
  12. 2026-08-18 22:28 UTCEG score recompute
  13. 2026-08-18 13:48 UTCEPSS rescore
  14. 2026-08-17 22:29 UTCEG score recompute
  15. 2026-08-17 13:47 UTCEPSS rescore
  16. 2026-08-16 22:23 UTCEG score recompute
  17. 2026-08-16 14:56 UTCEPSS rescore
  18. 2026-08-16 02:14 UTCEPSS rescore
  19. 2026-08-15 23:09 UTCEG score recompute
  20. 2026-08-15 01:30 UTCEPSS rescore
  21. 2026-08-14 00:41 UTCEG score recompute
  22. 2026-08-13 22:00 UTCEPSS rescore
  23. 2026-08-13 01:27 UTCEG score recompute
  24. 2026-08-12 13:51 UTCEPSS rescore
  25. 2026-08-12 02:14 UTCEG score recompute
Show 62 more
  1. 2026-08-11 03:00 UTCEG score recompute
  2. 2026-08-11 00:00 UTCEPSS rescore
  3. 2026-08-10 03:47 UTCEG score recompute
  4. 2026-08-09 13:46 UTCEPSS rescore
  5. 2026-08-09 04:33 UTCEG score recompute
  6. 2026-08-08 16:37 UTCEPSS rescore
  7. 2026-08-08 05:20 UTCEG score recompute
  8. 2026-08-07 06:06 UTCEG score recompute
  9. 2026-08-06 13:47 UTCEPSS rescore
  10. 2026-08-06 06:52 UTCEG score recompute
  11. 2026-08-05 19:17 UTCEPSS rescore
  12. 2026-08-05 07:38 UTCEG score recompute
  13. 2026-08-04 15:10 UTCEPSS rescore
  14. 2026-08-04 10:39 UTCEPSS rescore
  15. 2026-08-04 08:23 UTCEG score recompute
  16. 2026-08-03 10:36 UTCEPSS rescore
  17. 2026-08-02 08:35 UTCEG score recompute
  18. 2026-08-02 02:27 UTCEPSS rescore
  19. 2026-08-01 09:21 UTCEG score recompute
  20. 2026-08-01 04:16 UTCEPSS rescore
  21. 2026-07-31 10:07 UTCEG score recompute
  22. 2026-07-30 16:28 UTCEPSS rescore
  23. 2026-07-30 10:54 UTCEG score recompute
  24. 2026-07-30 01:30 UTCEPSS rescore
  25. 2026-07-30 01:30 UTCEPSS rescore
  26. 2026-07-29 11:39 UTCEG score recompute
  27. 2026-07-28 15:37 UTCEPSS rescore
  28. 2026-07-28 12:23 UTCEG score recompute
  29. 2026-07-27 14:14 UTCEPSS rescore
  30. 2026-07-27 11:42 UTCEG score recompute
  31. 2026-07-26 14:54 UTCEPSS rescore
  32. 2026-07-26 14:54 UTCEPSS rescore
  33. 2026-07-26 12:27 UTCEG score recompute
  34. 2026-07-25 14:18 UTCEPSS rescore
  35. 2026-07-25 14:18 UTCEPSS rescore
  36. 2026-07-24 14:18 UTCEPSS rescore
  37. 2026-07-24 14:18 UTCEPSS rescore
  38. 2026-07-23 14:18 UTCEPSS rescore
  39. 2026-07-23 14:18 UTCEPSS rescore
  40. 2026-07-23 03:21 UTCEG score recompute
  41. 2026-07-22 14:08 UTCEPSS rescore
  42. 2026-07-22 14:08 UTCEPSS rescore
  43. 2026-07-21 15:25 UTCEPSS rescore
  44. 2026-07-21 15:25 UTCEPSS rescore
  45. 2026-07-20 17:08 UTCEPSS rescore
  46. 2026-07-19 14:31 UTCEPSS rescore
  47. 2026-07-18 10:04 UTCEPSS rescore
  48. 2026-07-16 17:03 UTCEPSS rescore
  49. 2026-07-15 16:57 UTCEPSS rescore
  50. 2026-07-15 16:57 UTCEPSS rescore
  51. 2026-07-15 02:00 UTCEPSS rescore
  52. 2026-07-15 02:00 UTCEPSS rescore
  53. 2026-07-13 22:31 UTCEPSS rescore
  54. 2026-07-13 06:13 UTCEPSS rescore
  55. 2026-07-13 06:13 UTCEPSS rescore
  56. 2026-07-12 05:46 UTCEPSS rescore
  57. 2026-07-11 08:27 UTCEPSS rescore
  58. 2026-07-11 08:27 UTCEPSS rescore
  59. 2026-07-09 19:10 UTCEPSS rescore
  60. 2026-07-09 19:10 UTCEPSS rescore
  61. 2026-07-08 16:24 UTCEG score recompute
  62. 2026-07-08 16:24 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-59930?
CVE-2026-59930 is a medium vulnerability published on July 8, 2026. Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, the toc plugin and TableOfContents directive generate heading IDs as predictable tocN values without slugifying the heading text, allowing attacker-controlled id="tocN" content to collide with generated anchors and…
When was CVE-2026-59930 disclosed?
CVE-2026-59930 was first published in the National Vulnerability Database on July 8, 2026, with the most recent update on July 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-59930 actively exploited?
CVE-2026-59930 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 91.2% of all scored CVEs.
What is the CVSS score of CVE-2026-59930?
CVE-2026-59930 has a CVSS v3 base score of 4.3 (NVD).
How do I remediate CVE-2026-59930?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-59930, 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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