{"cve":"CVE-2023-36459","nvd":{"published":"2023-07-06T19:15:10.727","modified":"2026-06-17T06:06:18.330","status":"Modified","description":"Mastodon is a free, open-source social network server based on ActivityPub. Starting in version 1.3 and prior to versions 3.5.9, 4.0.5, and 4.1.3, an attacker using carefully crafted oEmbed data can bypass the HTML sanitization performed by Mastodon and include arbitrary HTML in oEmbed preview cards. This introduces a vector for cross-site scripting (XSS) payloads that can be rendered in the user's browser when a preview card for a malicious link is clicked through. Versions 3.5.9, 4.0.5, and 4.1.3 contain a patch for this issue.","cvss_v4":null,"cvss_v3":{"version":"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},"cwes":["CWE-79"],"references":["http://www.openwall.com/lists/oss-security/2023/07/06/5","https://github.com/mastodon/mastodon/commit/6d8e0fae3e96f3cf4febe03fa7fcf5b95ff761b2","https://github.com/mastodon/mastodon/releases/tag/v3.5.9","https://github.com/mastodon/mastodon/releases/tag/v4.0.5","https://github.com/mastodon/mastodon/releases/tag/v4.1.3"],"products":["joinmastodon:mastodon"],"source":"nvd","synced_at":"2026-10-19T21:38:30.124994567+00:00"},"epss":{"cve":"CVE-2023-36459","score":0.01217,"percentile":0.68609,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}