What is the CVSS score of CVE-2025-27157?

CVE-2025-27157 has a CVSS 3.1 base score of 5.3 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L. EPSS exploitation probability: 0.2%.

Which versions of Mastodon are affected by CVE-2025-27157?

Organizations using version 4.2.0 and should be aware of moderate risk from CVE-2025-27157 rated CVSS 5.3. Exploitation could compromise the security of affected deployments.. A patch is available.

How to fix or mitigate CVE-2025-27157?

Within 30 days: Identify affected systems running version 4.2.0 and and apply vendor patches as part of regular patch cycle. Vendor patch is available.

Mastodon CVE-2025-27157

MEDIUM

Allocation of Resources Without Limits or Throttling (CWE-770)

2025-02-27 security-advisories@github.com

Denial Of Service Mastodon

5.3

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

5.3 MEDIUM

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

Lifecycle Timeline

Analysis Generated

Mar 28, 2026 - 18:28 vuln.today

Patch released

Mar 28, 2026 - 18:28 nvd

Patch available

CVE Published

Feb 27, 2025 - 17:15 nvd

MEDIUM 5.3

DescriptionGitHub Advisory

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.

AnalysisAI

Mastodon is a self-hosted, federated microblogging platform. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Allocation of Resources Without Limits vulnerability could allow attackers to exhaust system resources through uncontrolled allocation.

Technical ContextAI

This vulnerability is classified as Allocation of Resources Without Limits (CWE-770), which allows attackers to exhaust system resources through uncontrolled allocation. 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. Affected products include: Joinmastodon Mastodon. Version information: version 4.2.0.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Set resource limits, implement rate limiting, validate input sizes.