CVE-2026-6827

MEDIUMPre-NVD 6.16.1—
EchelonGraph scoreMEDIUM 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: 0.3%CVSS: 6.1Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
6.1MEDIUMmedium confidence
EG Risk
28
EG Risk 28/100CISA SSVC

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%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
16th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

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
githubMentions a patch (unverified)

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 rangeFix by version rangeDependents
justhtml0.1.0 ... 1.9.1 (61 versions)
  • every version up to 1.17.0: fixed in 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 / 73× 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 128 total refreshes for this CVE.

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

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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 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 0.3% probability of exploitation in the next 30 days (16th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-6827?
CVE-2026-6827 has a CVSS base score of 6.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-6827?
A fix for CVE-2026-6827 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-6827 are linked in the Vendor Advisories panel on this page.

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