CVE-2025-27399
5.3 · MEDIUMOverview
CVE-2025-27399 is a medium-severity vulnerability affecting joinmastodon mastodon. It was published on February 27, 2025 and has a CVSS 3.1 base score of 5.3 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.3, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
Mastodon is a self-hosted, federated microblogging platform. In versions prior to 4.1.23, 4.2.16, and 4.3.4, when the visibility for domain blocks/reasons is set to "users" (localized English string: "To logged-in users"), users that are not yet approved can view the block reasons. Instance admins that do not want their domain blocks to be public are impacted. Versions 4.1.23, 4.2.16, and 4.3.4 fix the issue.
Remediation
Check the references section for vendor advisories and patches from joinmastodon. Update mastodon to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| joinmastodon | mastodon | >= 0, < 4.1.23 | Affected |
References
Frequently Asked Questions
What is CVE-2025-27399?
CVE-2025-27399 is a medium-severity vulnerability affecting joinmastodon mastodon. It was published on February 27, 2025 and has a CVSS 3.1 base score of 5.3 (MEDIUM).
How severe is CVE-2025-27399?
This vulnerability has a CVSS 3.1 base score of 5.3, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2025-27399?
Check the references section for vendor advisories and patches from joinmastodon. Update mastodon to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2025-27399?
CyberStrike's AI-powered security agents can automatically detect CVE-2025-27399 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
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