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Vulnerability · Published Mar 27, 2026 · Assigned by GitHub_M

CVE-2026-33869Mastodon has a denial of service for quote authorization

Medium 4.8

In plain English

A medium-severity incorrect authorization 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 0.2% (higher than 7% of all known vulnerabilities).

Severity (CVSS 3.1)4.8Medium
Exploit odds (30 days)0.2%top 93.3% 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. In versions on the 4.5.x branch prior to 4.5.8 and on the 4.4.x branch prior to 4.4.15, an attacker that knows of a quote before it has reached a server can prevent it from being correctly processed on that server. The vulnerability has been patched in Mastodon 4.5.8 and 4.4.15. Mastodon 4.3 and earlier are not affected because they do not support quotes.

Affected products (as reported)

VendorProductVersions
mastodon mastodon >= 4.5.0, < 4.5.8>= 4.4.0, < 4.4.15

Weakness: CWE-863 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L

References