TI-2026-06871 Aliases CVE-2026-7808 GHSA-fj35-9vw4-h76v

justhtml before 1.16.0 Multiple Security Issues via Sanitization

MEDIUM 49CWE-20Published 2026-08-23 · Updated 2026-08-24

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Attack requirements: None
Impact type: —
Confidentiality · integrity · availability: High · High · High
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00587 48th percentileScored 2026-11-07

Fix Fixed justhtml (EmilStenstrom): 1.16.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
EmilStenstrom	justhtml	before 1.16.0	1.16.0	Patch available	CNA

justhtml VendorEmilStenstrom Affected before 1.16.0 Fixed in 1.16.0 Patch available CNA

Remediation

Fix · CNA justhtml (EmilStenstrom) Fixed in 1.16.0

Timeline

2026-10-02 Threatist record created from CVE-2026-7808
2026-10-03 Alias added: GHSA-fj35-9vw4-h76v

References

Advisory 1

GitHub Security Advisory (GHSA-4p64-v8f5-r2gx)

TI-2026-07422 justhtml before 1.12.0 Sanitizer Bypass via Markdown CVSS 4.0CRITICAL 9.3
TI-2026-08560 justhtml before 1.10.0 Denial of Service via deeply nested HTML CVSS 4.0HIGH 8.7
TI-2026-52557 justhtml before 3.11.0 XSS via selectedcontent projection CVSS 4.0MEDIUM 5.1
TI-2026-04717 justhtml before 1.13.0 XSS via code fence breakout CVSS 4.0MEDIUM 5.1
TI-2026-04716 justhtml before 1.15.0 Multiple Security Issues CVSS 4.0CRITICAL 9.3
TI-2026-04066 justhtml before 1.18.0 Denial of Service via CSS Selector CVSS 4.0HIGH 8.7

See all 10 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences