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Vulnerability · Published Jul 6, 2023 · Assigned by GitHub_M

CVE-2023-36459Mastodon vulnerable to Cross-site Scripting through oEmbed preview cards

Critical 9.3

In plain English

A critical-severity cross-site scripting in mastodon from mastodon. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.2% (higher than 69% of all known vulnerabilities).

Severity (CVSS 3.1)9.3Critical
Exploit odds (30 days)1.2%top 31.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

VendorProductVersions
mastodon mastodon >= 1.3, < 3.5.9>= 4.0.0, < 4.0.5>= 4.1.0, < 4.1.3

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

References