CVE-2025-27157
Mastodon's rate-limits are missing on `/auth/setup`
5.3
MEDIUM
CVSS 3.1
EPSS 0.24%
Description
Mastodon is a self-hosted, federated microblogging platform. Starting in version 4.2.0 and prior to versions 4.2.16 and 4.3.4, the rate limits are missing on `/auth/setup`. Without those rate limits, an attacker can craft requests that will send an email to an arbitrary addresses. Versions 4.2.16 and 4.3.4 fix the issue.
How to fix CVE-2025-27157
To remediate CVE-2025-27157, upgrade the affected package to a fixed version below.
- —upgrade to 4.3.4 or later
Is CVE-2025-27157 being exploited?
Low — EPSS is 0.2%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- >= 4.2.0, < 4.3.4
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |