CVE-2026-33869
Medium
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.
SeverityMedium
CVSS4.8
Exploit probability—
Product
Mastodon
PublishedMar 27, 2026
First seenMar 27, 2026
Weakness typeCWE-863Incorrect authorization
How to fix
Update
- joinmastodon mastodon4.4.15, 4.5.8 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| joinmastodon mastodon | 4.4.0 ≤ v < 4.4.15, 4.5.0 ≤ v < 4.5.8 | 4.4.15, 4.5.8 |
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