XSS in Joinmastodon Mastodon

CVE-2023-36459

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 b…

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.012 (65.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.3 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2023-36459?
CVE-2023-36459 is a critical-severity vulnerability in Joinmastodon Mastodon, classified under Cross-site Scripting. CVSS score: 9.3/10. Published 2023-07-06.
How severe is CVE-2023-36459?
Critical severity. CVSS v3 base score is 9.3 out of 10.
Is CVE-2023-36459 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.