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OpenAdvisories
Medium · 4.8 CVE-2026-33869 EUVD-2026-16785

Mastodon has a denial of service for quote authorization

Published Mar 27, 2026 · Updated Mar 27, 2026 · Assigned by GitHub_M

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

VendorProductAffectedFixed
mastodon mastodon >= 4.5.0, < 4.5.8, >= 4.4.0, < 4.4.15 —

References