{"id":"CVE-2026-7808","state":"PUBLISHED","title":"justhtml before 1.16.0 Multiple Security Issues via Sanitization","description":"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.","publishedAt":"2026-08-23T13:34:13.232Z","updatedAt":"2026-08-24T18:14:27.467Z","severity":{"score":9.3,"label":"Critical","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","source":"VulnCheck"},"assigner":"VulnCheck","products":["EmilStenstrom justhtml"],"affected":[{"vendor":"EmilStenstrom","product":"justhtml","packageURL":"pkg:pypi/justhtml","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"1.16.0","versionType":"semver"},{"version":"1.16.0","status":"unaffected","versionType":"semver"}]}],"references":["https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-4p64-v8f5-r2gx","https://www.vulncheck.com/advisories/justhtml-before-multiple-security-issues-via-sanitization"],"weaknesses":["CWE-20"],"ingestedAt":"2026-10-29T20:13:07.220Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/7xxx/CVE-2026-7808.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-7808","state":"PUBLISHED","datePublished":"2026-08-23T13:34:13.232Z","dateUpdated":"2026-08-24T18:14:27.467Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-05-04T21:13:37.078Z"},"containers":{"cna":{"title":"justhtml before 1.16.0 Multiple Security Issues via Sanitization","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"EmilStenstrom","product":"justhtml","packageURL":"pkg:pypi/justhtml","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"1.16.0","versionType":"semver"},{"version":"1.16.0","status":"unaffected","versionType":"semver"}]}],"references":[{"url":"https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-4p64-v8f5-r2gx","tags":["vendor-advisory"],"name":"GitHub Security Advisory (GHSA-4p64-v8f5-r2gx)"},{"url":"https://www.vulncheck.com/advisories/justhtml-before-multiple-security-issues-via-sanitization","name":"VulnCheck Advisory: justhtml before 1.16.0 Multiple Security Issues via Sanitization","tags":["third-party-advisory"]}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":9.3,"baseSeverity":"CRITICAL","exploitMaturity":"NOT_DEFINED","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS"},{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":9.8,"baseSeverity":"CRITICAL","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"format":"CVSS"}],"problemTypes":[{"descriptions":[{"cweId":"CWE-20","lang":"en","description":"Improper Input Validation","type":"CWE"}]}],"providerMetadata":{"shortName":"VulnCheck","orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateUpdated":"2026-08-23T13:34:13.232Z"},"datePublic":"2026-04-12T00:00:00.000Z","credits":[{"lang":"en","value":"EmilStenstrom","type":"coordinator"}],"x_generator":{"engine":"vulncheck-endgame"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-24T18:14:13.443990Z","id":"CVE-2026-7808","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-24T18:14:27.467Z"}}]}}}