Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2025-53859

Severity CVSS v4.0:
MEDIUM
Type:
CWE-125 Out-of-bounds Read
Publication date:
13/08/2025
Last modified:
04/11/2025

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.<br /> <br /> <br /> <br /> <br /> Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Impact

Vector 4.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N CVSS v4.0 Severity and Metrics:

Base Score: 6.30 MEDIUM
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): Present
Privileges Required (PR): None
User Interaction (UI): None
Confidentiality (VC): Low
Integrity (VI): None
Availability (VA): None
Confidentiality (SC): None
Integrity (SI): None
Availability (SA): None

Base Score 4.0
6.30
Severity 4.0
MEDIUM
Vector 3.x
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N CVSS v3.1 Severity and Metrics:

Base Score: 3.70 LOW
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Attack Vector (AV): Network
Attack Complexity (AC): High
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): Low
Integrity (I): None
Availability (A): None

Base Score 3.x
3.70
Severity 3.x
LOW

Vulnerable products and versions

CPE From Up to
cpe:2.3:a:f5:nginx_plus:r30:-:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r31:-:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r32:-:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r32:p1:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r32:p2:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r33:-:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r33:p1:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r33:p2:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r34:-:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r34:p1:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:* 0.7.22 (including) 1.29.1 (excluding)

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools