{"id":"CVE-2026-7808","title":"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","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 ad…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-20"],"vendor":"justhtml","product":"justhtml","affected":["justhtml < 1.16.0"],"patched":["justhtml 1.16.0"],"published":"2026-08-23","updated":"2026-10-12","sourceUpdated":"2026-10-12T16:10:00.220","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-7808","references":[{"url":"https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-4p64-v8f5-r2gx","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/justhtml-before-multiple-security-issues-via-sanitization","label":"disclosure@vulncheck.com"},{"url":"https://github.com/EmilStenstrom/justhtml"}],"tags":["nvd","osv","pip"],"epss":0.00587,"epssPercentile":0.47875,"aliases":["GHSA-4p64-v8f5-r2gx"],"ecosystem":"pip","ingestedAt":"2026-08-24T19:25:44.052Z","slug":"CVE-2026-7808","body":"## Overview\n\njusthtml 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-7808)\n\nAffected packages:\n\n- `justhtml < 1.16.0`\n\nPatched in:\n\n- `justhtml 1.16.0`\n\nSource: https://osv.dev/vulnerability/GHSA-4p64-v8f5-r2gx","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":219489,"id":"CVE-2026-7808","ts":1791824361490,"field":"cvss","old":null,"new":"9.8"},{"seq":219488,"id":"CVE-2026-7808","ts":1791824361490,"field":"severity","old":"low","new":"critical"}]}