CVE-2026-6827 (GCVE-0-2026-6827)

Vulnerability from cvelistv5 – Published: 2026-08-23 13:34 – Updated: 2026-08-29 11:47
VLAI
Title
justhtml before 1.17.0 Multiple Cross-Site Scripting Vulnerabilities
Summary
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 encoding="text/html">) and mutation-XSS parser-differential payloads could survive sanitization and become active HTML after reparse; SVG filter="url(...)" and preserved <style> 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.
Severity
5.1 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
6.1 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-26 18:05 UTC
CWE
  • CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Assigner
VulnCheck CNA under the mitre root
CNA scorecard B 84/100 over 6373 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
EmilStenstrom justhtml Affected: 0 , < 1.17.0 (semver)
Unaffected: 1.17.0 (semver)
guessed Create a notification for this product.
Date Public
2026-04-19 00:00
Credits
EmilStenstrom
Show details on NVD website
To clipboard 

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