{"id":"CVE-2026-65903","revision":null,"records":[{"revision":"4c8588dc20d7484b97d0adaf7ac20983","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-65903","aliases":[],"title":"DOMPurify before 3.4.0 ADD_TAGS Function Bypasses FORBID_TAGS","description":"DOMPurify before 3.4.0 contains a logic error in the ADD_TAGS function where short-circuit evaluation allows forbidden tags to bypass FORBID_TAGS restrictions. Attackers can craft input containing tags listed in FORBID_TAGS that are also added via ADD_TAGS function, causing them to be retained in sanitized output.","state":0,"publishedAt":"2026-07-23T13:16:21.187+00:00","modifiedAt":"2026-07-23T15:35:54.823+00:00","affected":[{"ecosystem":"Vendor product","name":"DOMPurify","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"cure53\",\n                    \"product\": \"DOMPurify\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"packageURL\": \"pkg:npm/dompurify\",\n                    \"versions\": [\n                        {\n                            \"version\": \"0\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\",\n                            \"lessThan\": \"3.4.0\"\n                        },\n                        {\n                            \"version\": \"3.4.0\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","score":5.1,"severity":"MEDIUM"},{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1,"severity":"MEDIUM"}],"references":["https://github.com/cure53/DOMPurify/security/advisories/GHSA-39q2-94rc-95cp","https://www.vulncheck.com/advisories/dompurify-before-add-tags-function-bypasses-forbid-tags"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-65903","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-65903","identifiers":["CVE-2026-65903"]},"retained":false,"historicalAffected":[]},{"revision":"13444c1787ce443289f54b1ffd32d794","observedAt":"2026-10-25T15:18:51.467+00:00","statement":{"source":"nvd","id":"CVE-2026-65903","aliases":[],"title":"DOMPurify before 3.4.0 contains a logic error in the ADD_TAGS function where short-circuit evaluation allows forbidden tags to bypass FORBID_TAGS restrictions. Attackers can craft input containing tags listed in FORBID_TAGS that are also ad…","description":"DOMPurify before 3.4.0 contains a logic error in the ADD_TAGS function where short-circuit evaluation allows forbidden tags to bypass FORBID_TAGS restrictions. Attackers can craft input containing tags listed in FORBID_TAGS that are also added via ADD_TAGS function, causing them to be retained in sanitized output.","state":0,"publishedAt":"2026-07-23T14:18:05.903+00:00","modifiedAt":"2026-10-24T13:10:00.147+00:00","affected":[],"metrics":[{"system":"CVSS 4.0 · disclosure@vulncheck.com · Secondary","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","score":5.1,"severity":"MEDIUM"},{"system":"CVSS 3.1 · disclosure@vulncheck.com · Secondary","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1,"severity":"MEDIUM"}],"references":["https://github.com/cure53/DOMPurify/security/advisories/GHSA-39q2-94rc-95cp","https://www.vulncheck.com/advisories/dompurify-before-add-tags-function-bypasses-forbid-tags"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-65903","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Analyzed","weaknesses":["CWE-697"],"productCriteria":["cpe:2.3:a:cure53:dompurify:*:*:*:*:*:*:*:*"],"sourceDates":{"published":"2026-07-23T14:18:05.903","lastModified":"2026-10-24T13:10:00.147"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-65903","identifiers":["CVE-2026-65903"]},"retained":false,"historicalAffected":[]},{"revision":"6d13b01a418d4815a2beb831ed417188","observedAt":"2026-10-24T13:17:17.793+00:00","statement":{"source":"osv","id":"GHSA-39q2-94rc-95cp","aliases":["CVE-2026-65903"],"title":"DOMPurify's ADD_TAGS function form bypasses FORBID_TAGS due to short-circuit evaluation","description":"## Summary\nIn `src/purify.ts:1117-1123`, `ADD_TAGS` as a function (via `EXTRA_ELEMENT_HANDLING.tagCheck`) bypasses `FORBID_TAGS` due to short-circuit evaluation.\n\nThe condition:\n```\n!(tagCheck(tagName)) && (!ALLOWED_TAGS[tagName] || FORBID_TAGS[tagName])\n```\nWhen `tagCheck(tagName)` returns `true`, the entire condition is `false` and the element is kept — `FORBID_TAGS[tagName]` is never evaluated.\n\n## Inconsistency\nThis contradicts the attribute-side pattern at line 1214 where `FORBID_ATTR` explicitly wins first:\n```\nif (FORBID_ATTR[lcName]) { continue; }\n```\nFor tags, FORBID should also take precedence over ADD.\n\n## Impact\nApplications using both `ADD_TAGS` as a function and `FORBID_TAGS` simultaneously get unexpected behavior — forbidden tags are allowed through. Config-dependent but a genuine logic inconsistency.\n\n## Suggested Fix\nCheck `FORBID_TAGS` before `tagCheck`:\n```\nif (FORBID_TAGS[tagName]) { /* remove */ }\nelse if (tagCheck(tagName) || ALLOWED_TAGS[tagName]) { /* keep */ }\n```\n\n## Affected Version\nv3.3.3 (commit 883ac15)","state":0,"publishedAt":"2026-04-16T00:46:35+00:00","modifiedAt":"2026-09-10T03:50:42.3794514+00:00","affected":[{"ecosystem":"npm","name":"dompurify","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"3.4.0"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V4","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"MODERATE"}],"references":["https://github.com/cure53/DOMPurify/security/advisories/GHSA-39q2-94rc-95cp","https://github.com/cure53/DOMPurify"],"sourceUrl":"https://github.com/advisories/GHSA-39q2-94rc-95cp","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-39q2-94rc-95cp","identifiers":["GHSA-39q2-94rc-95cp","CVE-2026-65903"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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