Mastodon is a free, open-source social network server based on ActivityPub. In versions on the 4.x branch prior to versions 4.0.10, 4.2.8, and 4.2.0-rc2, under certain conditions, attackers can abuse the translation feature to bypass the server-side HTML sanitization, allowing unescaped HTML to execute in the browser. The impact is limited thanks to Mastodon's strict Content Security Policy, blocking inline scripts, etc. However a CSP bypass or loophole could be exploited to execute malicious XSS. Furthermore, it requires user interaction, as this can only occur upon clicking the “Translate” button on a malicious post. Versions 4.0.10, 4.2.8, and 4.2.0-rc2 contain a patch for this issue.
{ "cpes": [ "cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:*", "cpe:2.3:a:joinmastodon:mastodon:4.2.0:beta1:*:*:*:*:*:*", "cpe:2.3:a:joinmastodon:mastodon:4.2.0:beta2:*:*:*:*:*:*", "cpe:2.3:a:joinmastodon:mastodon:4.2.0:beta3:*:*:*:*:*:*", "cpe:2.3:a:joinmastodon:mastodon:4.2.0:rc1:*:*:*:*:*:*" ], "severity": "Medium" }