CVE-2026-59923

MEDIUMPre-NVD 6.16.1—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 72% 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
6.1EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.1Exploit: 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, HTMLRenderer.safe_url() does not block percent-encoded javascript URIs, allowing attacker-supplied Markdown links or images to bypass URL protections and execute script in rendered HTML. This issue is fixed in version 3.3.0.

CVSS v3
6.1
EG Score
6.1(medium)
EG Risk
43(Track)
EG Risk 43/100SSVC: 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
Severity61% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
28%
KEV
Not listed

Published

July 8, 2026

Last Modified

July 9, 2026

Advisory Details (3)

Auto-updated Jul 8, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_release, github.
github Patch Available🟡 PoC Available

XSS via percent-encoded javascript URI bypass in safe_url() · Advisory · lepture/mistune · GitHub

https://github.com/lepture/mistune/security/advisories/GHSA-8c25-4j27-2rv3
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 c7101fcbb6e8 (lepture/mistune)

Patch available: lepture/mistune v3.3.0 (contains commit c7101fcbb6e8)

https://github.com/lepture/mistune/commit/c7101fcbb6e8790e8e39157c5ca2238fc6dd6cbc

Vendor Advisories for CVE-2026-59923(1)

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

Affected Packages

(5 across 5 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
mistune0.8.4-4 ... 3.1.4-1 (15 versions)——
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(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 48× 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. 2026-08-30 07:31 UTCEG score recompute
  2. 2026-08-30 01:22 UTCEPSS rescore
  3. 2026-08-28 21:42 UTCEPSS rescore
  4. 2026-08-27 21:50 UTCEG score recompute
  5. 2026-08-27 14:25 UTCEPSS rescore
  6. 2026-08-26 14:46 UTCEPSS rescore
  7. 2026-08-26 08:24 UTCEG score recompute
  8. 2026-08-25 13:49 UTCEPSS rescore
  9. 2026-08-24 20:33 UTCEG score recompute
  10. 2026-08-23 19:03 UTCEG score recompute
  11. 2026-08-23 00:19 UTCEPSS rescore
  12. 2026-08-22 20:47 UTCEG score recompute
  13. 2026-08-21 23:49 UTCEPSS rescore
  14. 2026-08-21 00:15 UTCEG score recompute
  15. 2026-08-20 22:55 UTCEPSS rescore
  16. 2026-08-20 01:59 UTCEG score recompute
  17. 2026-08-19 17:04 UTCEPSS rescore
  18. 2026-08-18 20:45 UTCEG score recompute
  19. 2026-08-18 13:48 UTCEPSS rescore
  20. 2026-08-17 22:29 UTCEG score recompute
  21. 2026-08-17 13:47 UTCEPSS rescore
  22. 2026-08-16 21:06 UTCEG score recompute
  23. 2026-08-16 14:56 UTCEPSS rescore
  24. 2026-08-16 02:14 UTCEPSS rescore
  25. 2026-08-15 22:50 UTCEG score recompute
Show 64 more
  1. 2026-08-15 01:30 UTCEPSS rescore
  2. 2026-08-14 02:18 UTCEG score recompute
  3. 2026-08-13 22:00 UTCEPSS rescore
  4. 2026-08-13 04:03 UTCEG score recompute
  5. 2026-08-12 13:51 UTCEPSS rescore
  6. 2026-08-12 05:47 UTCEG score recompute
  7. 2026-08-11 07:25 UTCEG score recompute
  8. 2026-08-11 00:00 UTCEPSS rescore
  9. 2026-08-10 09:09 UTCEG score recompute
  10. 2026-08-09 13:46 UTCEPSS rescore
  11. 2026-08-09 10:54 UTCEG score recompute
  12. 2026-08-08 16:37 UTCEPSS rescore
  13. 2026-08-08 12:38 UTCEG score recompute
  14. 2026-08-06 16:07 UTCEG score recompute
  15. 2026-08-06 13:47 UTCEPSS rescore
  16. 2026-08-05 19:17 UTCEPSS rescore
  17. 2026-08-04 19:35 UTCEG score recompute
  18. 2026-08-04 15:10 UTCEPSS rescore
  19. 2026-08-04 10:39 UTCEPSS rescore
  20. 2026-08-02 23:04 UTCEG score recompute
  21. 2026-08-02 02:27 UTCEPSS rescore
  22. 2026-08-02 00:48 UTCEG score recompute
  23. 2026-08-01 04:16 UTCEPSS rescore
  24. 2026-07-31 04:10 UTCEG score recompute
  25. 2026-07-30 16:28 UTCEPSS rescore
  26. 2026-07-30 05:54 UTCEG score recompute
  27. 2026-07-30 01:30 UTCEPSS rescore
  28. 2026-07-30 01:30 UTCEPSS rescore
  29. 2026-07-29 07:33 UTCEG score recompute
  30. 2026-07-28 15:37 UTCEPSS rescore
  31. 2026-07-28 09:04 UTCEG score recompute
  32. 2026-07-27 14:14 UTCEPSS rescore
  33. 2026-07-27 10:44 UTCEG score recompute
  34. 2026-07-26 14:54 UTCEPSS rescore
  35. 2026-07-26 14:54 UTCEPSS rescore
  36. 2026-07-26 12:27 UTCEG score recompute
  37. 2026-07-25 14:18 UTCEPSS rescore
  38. 2026-07-25 14:18 UTCEPSS rescore
  39. 2026-07-24 14:18 UTCEPSS rescore
  40. 2026-07-24 14:18 UTCEPSS rescore
  41. 2026-07-23 14:18 UTCEPSS rescore
  42. 2026-07-23 14:18 UTCEPSS rescore
  43. 2026-07-23 03:21 UTCEG score recompute
  44. 2026-07-22 14:08 UTCEPSS rescore
  45. 2026-07-22 14:08 UTCEPSS rescore
  46. 2026-07-21 15:25 UTCEPSS rescore
  47. 2026-07-21 15:25 UTCEPSS rescore
  48. 2026-07-20 17:08 UTCEPSS rescore
  49. 2026-07-19 14:31 UTCEPSS rescore
  50. 2026-07-19 02:29 UTCEPSS rescore
  51. 2026-07-18 10:04 UTCEPSS rescore
  52. 2026-07-16 17:03 UTCEPSS rescore
  53. 2026-07-15 02:00 UTCEPSS rescore
  54. 2026-07-15 02:00 UTCEPSS rescore
  55. 2026-07-13 22:31 UTCEPSS rescore
  56. 2026-07-13 06:13 UTCEPSS rescore
  57. 2026-07-13 06:13 UTCEPSS rescore
  58. 2026-07-12 05:46 UTCEPSS rescore
  59. 2026-07-11 08:27 UTCEPSS rescore
  60. 2026-07-11 08:27 UTCEPSS rescore
  61. 2026-07-09 19:10 UTCEPSS rescore
  62. 2026-07-09 19:10 UTCEPSS rescore
  63. 2026-07-08 16:24 UTCEG score recompute
  64. 2026-07-08 16:24 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-59923?
CVE-2026-59923 is a medium vulnerability published on July 8, 2026. Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, HTMLRenderer.safe_url() does not block percent-encoded javascript URIs, allowing attacker-supplied Markdown links or images to bypass URL protections and execute script in rendered HTML. This issue is fixed in version…
When was CVE-2026-59923 disclosed?
CVE-2026-59923 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-2026-59923 actively exploited?
CVE-2026-59923 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 72.5% of all scored CVEs.
What is the CVSS score of CVE-2026-59923?
CVE-2026-59923 has a CVSS v3 base score of 6.1 (NVD).
How do I remediate CVE-2026-59923?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-59923, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-59923

Explore →

Is Your Infrastructure Affected by CVE-2026-59923?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs