CVE-2026-7808

CVE-2026-7808

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.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-7808?
CVE-2026-7808 is a critical-severity vulnerability, classified under Improper Input Validation. CVSS score: 9.8/10. Published 2026-08-23.
How severe is CVE-2026-7808?
Critical severity. CVSS v3 base score is 9.8 out of 10.