CVE-2026-7808justhtml before 1.16.0 Multiple Security Issues via Sanitization
Updated under an hour ago ()
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It affects EmilStenstrom justhtml. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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justhtml before 1.16.0 contains multiple HTML sanitization bypass issues that can allow active/dangerous content (e.g., script or style) to survive sanitization, potentially leading to cross-site scripting. The issues primarily affect advanced usage rather than the default JustHTML(..., sanitize=True) path for ordinary parsed HTML: mutating or reusing sanitization policy objects (including exported defaults) could weaken later sanitization; programmatic DOM input to sanitize()/sanitize_dom() could miss mixed-case tag names (e.g., ScRiPt, StYlE); crafted programmatic doctype names could serialize into active markup; and custom policies preserving SVG or MathML could allow animation elements, presentation attributes with external url(...) references, or DOM trees mislabeled as namespace="html" to bypass foreign-content checks. Fixed in 1.16.0.
- CVSS
- 9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-20
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- VulnCheck
- NVD analysis
- Deferred
- Record last updated
- Aug 24, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
EmilStenstrom justhtml emilstenstrom:justhtml (from the name) | before 1.16.0; 1.16.0 not affected | CNA record |
References
- https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-4p64-v8f5-r2gxvendor-advisory
- https://www.vulncheck.com/advisories/justhtml-before-multiple-security-issues-via-sanitizationthird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.