Is CVE-2025-27157 in the CISA KEV catalog?

No. CVE-2025-27157 is not currently on the CISA Known Exploited Vulnerabilities list.

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

CVE-2025-27157 has a CVSS v3 base score of 5.3 (MEDIUM).

What is the EPSS score for CVE-2025-27157?

CVE-2025-27157 has an EPSS score of 0.34% (26th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2025-27157?

Upgrade mastodon to 4.3.4 or later.

CVE & CISA-KEV Catalog

CVE-2025-27157

MEDIUM

5.3

CVSS v3

NVD

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.

CWE-770Allocation of Resources Without Limits or Throttling

How to fix

Remediation Available

mastodonNVD

Affected:>= 4.3.0, < 4.3.4Fixed in:4.3.4CVE-2025-27157derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityLow

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

Exploit Intelligence

0.34%probability of exploitation in 30 days

26thpercentile

Low risk: more likely to be exploited than 26% of all known CVEs.

References

Patch1

github.com

Vendor Advisory1

github.com

Related Vulnerabilities

Other CWE-770 (Allocation of Resources Without Limits or Throttling) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-50387	High	7.5	100%	-	Fix
CVE-2019-11478	Medium	5.3	95%	-	Fix
CVE-2019-11479	High	7.5	92%	-	Fix
CVE-2024-27316	High	7.5	91%	-	Fix
CVE-2022-30522	High	7.5	90%	-	Fix
CVE-2019-9515	High	7.5	88%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-06-24.