{"id":"CVE-2026-33500","summary":"AVideo Vulnerable to Stored XSS via Markdown `javascript:` URI Bypasses ParsedownSafeWithLinks Sanitization","details":"WWBN AVideo is an open source video platform. In versions up to and including 26.0, the fix for CVE-2026-27568 (GHSA-rcqw-6466-3mv7) introduced a custom `ParsedownSafeWithLinks` class that sanitizes raw HTML `\u003ca\u003e` and `\u003cimg\u003e` tags in comments, but explicitly disables Parsedown's `safeMode`. This creates a bypass: markdown link syntax `[text](javascript:alert(1))` is processed by Parsedown's `inlineLink()` method, which does not go through the custom `sanitizeATag()` sanitization (that only handles raw HTML tags). With `safeMode` disabled, Parsedown's built-in `javascript:` URI filtering (`sanitiseElement()`/`filterUnsafeUrlInAttribute()`) is also inactive. An attacker can inject stored XSS via comment markdown links. Commit 3ae02fa240939dbefc5949d64f05790fd25d728d contains a patch.","aliases":["GHSA-72h5-39r7-r26j"],"modified":"2026-04-10T05:42:49.577604Z","published":"2026-03-23T16:24:52.892Z","database_specific":{"cwe_ids":["CWE-79"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33500.json","cna_assigner":"GitHub_M"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33500.json"},{"type":"FIX","url":"https://github.com/WWBN/AVideo/commit/3ae02fa240939dbefc5949d64f05790fd25d728d"},{"type":"ADVISORY","url":"https://github.com/WWBN/AVideo/security/advisories/GHSA-72h5-39r7-r26j"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33500"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/wwbn/avideo","events":[{"introduced":"0"},{"last_affected":"aee1e11ee8d9343f87b7643e49cc32924b07979b"}],"database_specific":{"versions":[{"introduced":"0"},{"last_affected":"26.0"}]}}],"versions":["10.8","11","11.1","11.1.1","11.5","11.6","12.4","14.3","14.3.1","18.0","2.2","2.7","21.0","22.0","24.0","25.0","26.0","3.4","4.0","7.2","7.3","7.4","7.6","7.7","7.8","8.1","8.5","8.6","8.7","8.9","8.9.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33500.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N"}]}