CVE-2023-42452: 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…

PriorityP427medium5.4CVSS 3.1

AVNACLPRLUIRSCCLILAN

EPSS

0.39%

30.9th percentile

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.

Affected

6 ranges

Vendor	Product	Version range	Fixed in
joinmastodon	mastodon	—	—
joinmastodon	mastodon	>= 4.0.0 < 4.0.10	4.0.10
joinmastodon	mastodon	>= 4.1.0 < 4.1.8	4.1.8
mastodon	mastodon	—	—
mastodon	mastodon	—	—
mastodon	mastodon	—	—

Stop checking back — get the weekly exploitation signal.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.