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CVE

CVE-2025-27157

Mastodon is a self-hosted, federated microblogging platform. Starting in version 4.2.0 and prior to versions 4.2.16 and

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.

MEDIUM · CVSS 5.3 EPSS 0.00239
Schedule remediation
  • SSVC automatable: yes - attacks can be scripted at scale
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-770Allocation of Resources Without Limits or Throttling
▤

Affected Products & Versions

2
joinmastodon mastodon>= 4.2.0 and < 4.2.16
joinmastodon mastodon>= 4.3.0 and < 4.3.4
▣

Scoring & Timeline

5.3
MEDIUM · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD27 Feb 2025 · 05:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
🔗

References & Sources

2
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/mastodon/mastodon/commit/06f879ce9bea195344ac9f71e6799eea500628ecPatch
https://github.com/mastodon/mastodon/security/advisories/GHSA-v39f-c9jj-8w7hVendor Advisory
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