CVE-2025-67500
Mastodon Error Handling Discrepancy Enables Private Status Existence Enumeration
Description
Mastodon is a free, open-source social network server based on ActivityPub. Versions 4.2.27 and prior, 4.3.0 through 4.3.14, 4.4.0 through 4.4.9, 4.5.0 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.
How to fix CVE-2025-67500
To remediate CVE-2025-67500, upgrade the affected package to a fixed version below.
- —upgrade to 4.2.28 or later
Is CVE-2025-67500 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 4.2.28, >= 4.3.0, < 4.3.15, >= 4.4.0, < 4.4.10
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | LOW3.7 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N |