CVE-2025-53859
3.7 · LOWOverview
CVE-2025-53859 is a low-severity vulnerability affecting f5 nginx_plus. It was published on August 13, 2025 and has a CVSS 3.1 base score of 3.7 (LOW).
This vulnerability has a CVSS 3.1 base score of 3.7, rated LOW. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
NGINX Open Source and NGINX Plus have a vulnerability in the ngx_mail_smtp_module that might allow an unauthenticated attacker to over-read NGINX SMTP authentication process memory; as a result, the server side may leak arbitrary bytes sent in a request to the authentication server. This issue happens during the NGINX SMTP authentication process and requires the attacker to make preparations against the target system to extract the leaked data. The issue affects NGINX only if (1) it is built with the ngx_mail_smtp_module, (2) the smtp_auth directive is configured with method "none," and (3) the authentication server returns the "Auth-Wait" response header.
Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Remediation
Check the references section for vendor advisories and patches from f5. Update nginx_plus 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 |
|---|---|---|---|
| f5 | nginx_open_source | >= 0.7.22, < 1.29.1 | Affected |
Frequently Asked Questions
What is CVE-2025-53859?
CVE-2025-53859 is a low-severity vulnerability affecting f5 nginx_plus. It was published on August 13, 2025 and has a CVSS 3.1 base score of 3.7 (LOW).
How severe is CVE-2025-53859?
This vulnerability has a CVSS 3.1 base score of 3.7, rated LOW. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2025-53859?
Check the references section for vendor advisories and patches from f5. Update nginx_plus 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-2025-53859?
CyberStrike's AI-powered security agents can automatically detect CVE-2025-53859 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
AI agents map your attack surface to find vulnerabilities like this one.
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