CVE-2023-36459 - CVE House
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Status published Critical CVE-2023-36459

Mastodon vulnerable to Cross-site Scripting through oEmbed preview cards

Vulnerability 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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

No credits recorded in the NVD database.

Affected Vendor

Affected Software

mastodon
Vulnerable Versions:
>= 1.3, < 3.5.9, >= 4.0.0, < 4.0.5, >= 4.1.0, < 4.1.3

Timeline

Official Publish: July 6th, 2023
Last Modified: February 13th, 2025
Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

Weaknesses (CWE)