Vulnerability · Published Dec 9, 2025 · Assigned by GitHub_M
CVE-2025-67500Mastodon Error Handling Discrepancy Enables Private Status Existence Enumeration
Low 3.7
In plain English
A low-severity security flaw 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 13% of all known vulnerabilities).
Official description
Mastodon is a free, open-source social network server based on ActivityPub. Versions 4.2.27 and prior, 4.3.0-beta.1 through 4.3.14, 4.4.0-beta.1 through 4.4.9, 4.5.0-beta.1 through 4.5.2 have discrepancies in error handling which allow checking whether a given status exists by sending a request with a non-English Accept-Language header. Using this behavior, an attacker who knows the identifier of a particular status they are not allowed to see can confirm whether this status exists or not. This cannot be used to learn the contents of the status or any other property besides its existence. This issue is fixed in versions 4.2.28, 4.3.15, 4.4.10 and 4.5.3.
Affected products (as reported)
Weakness: CWE-204 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N