CVE-2025-53859

3.7 LOW
Published: August 13, 2025 Modified: November 04, 2025

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://my.f5.com/manage/s/article/K000152786
Source: f5sirt@f5.com
Vendor Advisory
http://www.openwall.com/lists/oss-security/2025/08/13/5
Source: af854a3a-2127-422b-91ae-364da2661108

2 reference(s) from NVD

Quick Stats

CVSS v3 Score
3.7 / 10.0
EPSS (Exploit Probability)
0.1%
26th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

f5