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)
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.006 (46.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 46th percentile — 46.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.002
Weakness classification (CWE)
References
- github.com/EmilStenstrom/justhtml/security/advisories/GHSA-4p64-v8f5-r2gx (vendor-advisory)
- www.vulncheck.com/advisories/justhtml-before-multiple-security-issues-via-sanit… (third-party-advisory)
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.