- Description
- 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.
- Source
- disclosure@vulncheck.com
- NVD status
- Received
CVSS 4.0
- Type
- Secondary
- Base score
- 5.1
- Impact score
- -
- Exploitability score
- -
- Vector string
- 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- Severity
- MEDIUM
CVSS 3.1
- Type
- Primary
- Base score
- 6.1
- Impact score
- 2.7
- Exploitability score
- 2.8
- Vector string
- CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- Severity
- MEDIUM
- disclosure@vulncheck.com
- CWE-79
- Hype score
- Not currently trending
🚨*CVE* CVE-2026-6827 justhtml before 1.17.0 contains multiple security issues in sanitization, serialization, and programmatic DOM handling. When custom policies preserve foreign namespaces… https://t.co/VrjayqUFH0 ----- Traducción: CVE-2026-6827 jus… https://t.co/utmtNg
@infoflowcloud
23 Aug 2026
13 Impressions
0 Retweets
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CVE-2026-6827 JustHTML Security Issues https://t.co/tQu2YBampN
@VulmonFeeds
23 Aug 2026
102 Impressions
0 Retweets
0 Likes
1 Bookmark
0 Replies
0 Quotes