CVE-2026-6827

MEDIUMPre-NVD 6.16.1—
EchelonGraph scoreHIGH confidence

Score 6.1 from GitHub Security Advisory published 2026-08-23. a secondary CVSS source baseline 6.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
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: None knownExposed: 0

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

justhtml before 1.17.0 contains multiple security issues in sanitization, serialization, and programmatic DOM handling. When custom policies preserve foreign namespaces (SVG/MathML), dangerous content such as HTML integration points (SVG , MathML ) and mutation-XSS parser-differential payloads could survive sanitization and become active HTML after reparse; SVG filter="url(...)" and preserved could leave resource-loading CSS (@import, background-image:url()). Programmatic script/style/Comment nodes could serialize into active markup. Additional hardening fixes address sanitize-pipeline cache mutation and DOM parent/child cycles that could cause infinite loops. Most issues affect advanced or custom configurations rather than the default JustHTML(..., sanitize=True) safe path.

CVSS v3
6.1
EG Score
6.1(high)
EG Risk
28(Track)
EG Risk 28/100SSVC: 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%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
9%
KEV
Not listed

Published

August 23, 2026

Last Modified

August 29, 2026

Advisory Details (2)

Auto-updated Aug 23, 2026
Patch available. Sources: github.
generic

justhtml before 1.17.0 Multiple Cross-Site Scripting Vulnerabilities | Advisories | VulnCheck

https://www.vulncheck.com/advisories/justhtml-before-multiple-cross-site-scripting-vulnerabilities
github Patch Available

Multiple security fixes in justhtml 1.16.0 found by LLM · Advisory · EmilStenstrom/justhtml · GitHub

https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-vrx2-77f2-ww34

Vendor Advisories for CVE-2026-6827(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 (61 versions)1.17.0—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 18× in last 7d / 79× 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. 2026-09-19 16:04 UTCEG score recompute
  2. 2026-09-19 16:04 UTCGHSA enrichment
  3. 2026-09-18 19:28 UTCEPSS rescore
  4. 2026-09-18 14:46 UTCEG score recompute
  5. 2026-09-18 14:46 UTCGHSA enrichment
  6. 2026-09-17 13:39 UTCEG score recompute
  7. 2026-09-17 13:39 UTCGHSA enrichment
  8. 2026-09-16 14:08 UTCEPSS rescore
  9. 2026-09-16 12:31 UTCEG score recompute
  10. 2026-09-16 12:31 UTCGHSA enrichment
  11. 2026-09-16 05:15 UTCEPSS rescore
  12. 2026-09-15 11:25 UTCEG score recompute
  13. 2026-09-15 11:25 UTCGHSA enrichment
  14. 2026-09-15 03:12 UTCEPSS rescore
  15. 2026-09-14 10:18 UTCEG score recompute
  16. 2026-09-14 10:18 UTCGHSA enrichment
  17. 2026-09-13 09:12 UTCEG score recompute
  18. 2026-09-13 09:12 UTCGHSA enrichment
  19. 2026-09-12 15:02 UTCEPSS rescore
  20. 2026-09-12 08:06 UTCEG score recompute
  21. 2026-09-12 08:06 UTCGHSA enrichment
  22. 2026-09-11 14:53 UTCEPSS rescore
  23. 2026-09-11 06:59 UTCEG score recompute
  24. 2026-09-11 06:59 UTCGHSA enrichment
  25. 2026-09-10 09:35 UTCEPSS rescore
Show 54 more
  1. 2026-09-10 05:52 UTCGHSA enrichment
  2. 2026-09-09 04:46 UTCEG score recompute
  3. 2026-09-09 04:46 UTCGHSA enrichment
  4. 2026-09-08 22:01 UTCEPSS rescore
  5. 2026-09-08 03:34 UTCEG score recompute
  6. 2026-09-08 03:34 UTCGHSA enrichment
  7. 2026-09-07 16:01 UTCEPSS rescore
  8. 2026-09-07 02:27 UTCEG score recompute
  9. 2026-09-07 02:27 UTCGHSA enrichment
  10. 2026-09-06 13:47 UTCEPSS rescore
  11. 2026-09-06 01:00 UTCEG score recompute
  12. 2026-09-06 01:00 UTCGHSA enrichment
  13. 2026-09-05 15:31 UTCEPSS rescore
  14. 2026-09-04 23:46 UTCEG score recompute
  15. 2026-09-04 23:46 UTCGHSA enrichment
  16. 2026-09-04 05:07 UTCEPSS rescore
  17. 2026-09-03 22:15 UTCGHSA enrichment
  18. 2026-09-02 20:51 UTCEG score recompute
  19. 2026-09-02 20:51 UTCGHSA enrichment
  20. 2026-09-02 14:12 UTCEPSS rescore
  21. 2026-09-01 16:19 UTCEG score recompute
  22. 2026-09-01 16:19 UTCGHSA enrichment
  23. 2026-09-01 13:54 UTCEPSS rescore
  24. 2026-09-01 04:40 UTCEPSS rescore
  25. 2026-08-31 14:45 UTCEG score recompute
  26. 2026-08-31 14:45 UTCGHSA enrichment
  27. 2026-08-30 19:17 UTCEPSS rescore
  28. 2026-08-30 13:30 UTCEG score recompute
  29. 2026-08-30 13:30 UTCGHSA enrichment
  30. 2026-08-30 01:22 UTCEPSS rescore
  31. 2026-08-29 12:23 UTCEG score recompute
  32. 2026-08-29 12:23 UTCGHSA enrichment
  33. 2026-08-29 12:04 UTCEG score recompute
  34. 2026-08-29 12:03 UTCGHSA enrichment
  35. 2026-08-29 00:31 UTCEG score recompute
  36. 2026-08-29 00:31 UTCGHSA enrichment
  37. 2026-08-28 21:42 UTCEPSS rescore
  38. 2026-08-27 20:34 UTCEG score recompute
  39. 2026-08-27 20:34 UTCGHSA enrichment
  40. 2026-08-26 19:23 UTCEG score recompute
  41. 2026-08-26 19:23 UTCGHSA enrichment
  42. 2026-08-26 18:41 UTCEG score recompute
  43. 2026-08-26 18:41 UTCGHSA enrichment
  44. 2026-08-26 17:25 UTCEG score recompute
  45. 2026-08-26 17:25 UTCGHSA enrichment
  46. 2026-08-26 14:47 UTCEPSS rescore
  47. 2026-08-25 16:36 UTCEG score recompute
  48. 2026-08-25 16:36 UTCGHSA enrichment
  49. 2026-08-25 13:49 UTCEPSS rescore
  50. 2026-08-24 15:26 UTCEG score recompute
  51. 2026-08-24 15:26 UTCGHSA enrichment
  52. 2026-08-23 14:20 UTCEG score recompute
  53. 2026-08-23 13:51 UTCEG score recompute
  54. 2026-08-23 13:50 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-6827?
CVE-2026-6827 is a medium vulnerability published on August 23, 2026. justhtml before 1.17.0 contains multiple security issues in sanitization, serialization, and programmatic DOM handling. When custom policies preserve foreign namespaces (SVG/MathML), dangerous content such as HTML integration points (SVG <foreignObject>, MathML <annotation-xml…
When was CVE-2026-6827 disclosed?
CVE-2026-6827 was first published in the National Vulnerability Database on August 23, 2026, with the most recent update on August 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-6827 actively exploited?
CVE-2026-6827 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 91.4% of all scored CVEs.
What is the CVSS score of CVE-2026-6827?
CVE-2026-6827 has a CVSS v3 base score of 6.1 (NVD).
How do I remediate CVE-2026-6827?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-6827, 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-2026-6827

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