XSS in Joinmastodon Mastodon
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 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.
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.004 (31.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
Affected products
- Joinmastodon Mastodon — versions 4.2.0
- Mastodon — versions >= 4.0.0, < 4.0.10, >= 4.1.0, < 4.1.8, >= 4.2.0-beta1, < 4.2.0-rc2
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
Frequently asked questions
- What is CVE-2023-42452?
- CVE-2023-42452 is a medium-severity vulnerability in Joinmastodon Mastodon, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2023-09-19.
- How severe is CVE-2023-42452?
- Medium severity. CVSS v3 base score is 6.1 out of 10.