CVE-2026-8445

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-08-23. a secondary CVSS source baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.8Exploit: Elevated riskExposed: 0

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

justhtml versions <= 1.11.0 (fixed in 1.12.0) do not sufficiently escape HTML-significant characters (angle brackets) in text nodes when converting a parsed document to Markdown via to_markdown(). While a small set of Markdown metacharacters are escaped, characters such as < and > are preserved, so untrusted input that is safe in to_html() — including entity-decoded text (e.g. <script>) or text from RCDATA/RAWTEXT-parsed elements like , , , and — can be emitted as raw HTML in the Markdown output, enabling a sanitizer bypass and potential cross-site scripting when that output is rendered.

CVSS v3
9.8
EG Score
9.8(high)
EG Risk
75(Attend)
EG Risk 75/100SSVC: Attend

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
Severity98% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
32%
KEV
Not listed

Published

August 23, 2026

Last Modified

August 26, 2026

Advisory Details (2)

Auto-updated Sep 16, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

Sanitizer Bypass (in Markdown) · Advisory · EmilStenstrom/justhtml · GitHub

https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-3rcm-vjrc-p45j
generic

justhtml before 1.12.0 Sanitizer Bypass via Markdown | Advisories | VulnCheck

https://www.vulncheck.com/advisories/justhtml-before-sanitizer-bypass-via-markdown

Vendor Advisories for CVE-2026-8445(1)

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

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
justhtml0.1.0 ... 1.9.1 (56 versions)1.12.0—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 56× in last 7d / 218× 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 218 total refreshes for this CVE.

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

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-8445?
CVE-2026-8445 is a critical vulnerability published on August 23, 2026. justhtml versions <= 1.11.0 (fixed in 1.12.0) do not sufficiently escape HTML-significant characters (angle brackets) in text nodes when converting a parsed document to Markdown via tomarkdown(). While a small set of Markdown metacharacters are escaped, characters such as < and > are preserved, so…
When was CVE-2026-8445 disclosed?
CVE-2026-8445 was first published in the National Vulnerability Database on August 23, 2026, with the most recent update on August 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-8445 actively exploited?
CVE-2026-8445 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 68.0% of all scored CVEs.
What is the CVSS score of CVE-2026-8445?
CVE-2026-8445 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-8445?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-8445, 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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