Nginx Open Source
CVE-2025-53859
MEDIUM
Severity by source
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Primary rating from NVD.
CVSS VectorNVD
Lifecycle Timeline
3DescriptionCVE.org
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.
AnalysisAI
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. Rated medium severity (CVSS 6.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Technical ContextAI
This vulnerability is classified as Out-of-bounds Read (CWE-125), which allows attackers to read data from memory outside the intended buffer boundaries. 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. Affected products include: F5 Nginx Plus, F5 Nginx Open Source.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate array indices and buffer lengths. Use memory-safe languages. Enable AddressSanitizer during testing.
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Same weakness CWE-125 – Out-of-bounds Read
View allSame technique Buffer Overflow
View allVendor StatusVendor
SUSE
Severity: Low| Product | Status |
|---|---|
| SUSE Linux Enterprise High Performance Computing 15 SP6 SUSE Linux Enterprise Module for Server Applications 15 SP6 SUSE Linux Enterprise Server 15 SP6 SUSE Linux Enterprise Server for SAP Applications 15 SP6 | Fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP7 SUSE Linux Enterprise Module for Server Applications 15 SP7 SUSE Linux Enterprise Server 15 SP7 SUSE Linux Enterprise Server for SAP Applications 15 SP7 | Fixed |
| openSUSE Leap 15.6 | Fixed |
| openSUSE Tumbleweed | Fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP7 | Fixed |
| SUSE Linux Enterprise Module for Server Applications 15 SP7 | Fixed |
| SUSE Linux Enterprise Server 15 SP7 | Fixed |
| SUSE Linux Enterprise Server 16.0 | Fixed |
| SUSE Linux Enterprise Server 16.1 | Fixed |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | Fixed |
| SUSE Linux Enterprise Server for SAP applications 16.0 | Fixed |
| SUSE Linux Enterprise Server for SAP applications 16.1 | Fixed |
| openSUSE Leap 15.6 | Fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP4 | Fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | Fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP5 | Fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | Fixed |
| SUSE Linux Enterprise Module for Server Applications 15 SP4 | Fixed |
| SUSE Linux Enterprise Module for Server Applications 15 SP5 | Fixed |
| SUSE Linux Enterprise Module for Server Applications 15 SP6 | Fixed |
| SUSE Linux Enterprise Server 15 SP4 | Fixed |
| SUSE Linux Enterprise Server 15 SP4-LTSS | Fixed |
| SUSE Linux Enterprise Server 15 SP5 | Fixed |
| SUSE Linux Enterprise Server 15 SP5-LTSS | Fixed |
| SUSE Linux Enterprise Server 15 SP6 | Fixed |
| SUSE Linux Enterprise Server 15 SP6-LTSS | Fixed |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | Fixed |
| SUSE Manager Proxy 4.3 | Fixed |
| SUSE Manager Proxy LTS 4.3 | Fixed |
| SUSE Manager Retail Branch Server 4.3 | Fixed |
| SUSE Manager Retail Branch Server LTS 4.3 | Fixed |
| SUSE Manager Server 4.3 | Fixed |
| SUSE Manager Server LTS 4.3 | Fixed |
| SUSE CaaS Platform 4.0 | Fixed |
| SUSE Enterprise Storage 6 | Fixed |
| SUSE Enterprise Storage 7 | Fixed |
| SUSE Enterprise Storage 7.1 | Fixed |
| SUSE Linux Enterprise High Performance Computing 15 | Fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP1 | Fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS | Fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS | Fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP2 | Fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP2-ESPOS | Fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS | Fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP3 | Fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP3-ESPOS | Fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS | Fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | Fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS | Fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP6 | Fixed |
| SUSE Linux Enterprise High Performance Computing 15-ESPOS | Fixed |
| SUSE Linux Enterprise High Performance Computing 15-LTSS | Fixed |
| SUSE Linux Enterprise Module for Server Applications 15 | Fixed |
| SUSE Linux Enterprise Module for Server Applications 15 SP1 | Fixed |
| SUSE Linux Enterprise Module for Server Applications 15 SP2 | Fixed |
| SUSE Linux Enterprise Module for Server Applications 15 SP3 | Fixed |
| SUSE Linux Enterprise Real Time 15 SP2 | Fixed |
| SUSE Linux Enterprise Real Time 15 SP3 | Fixed |
| SUSE Linux Enterprise Real Time 15 SP4 | Fixed |
| SUSE Linux Enterprise Server 15 | Fixed |
| SUSE Linux Enterprise Server 15 SP1 | Fixed |
| SUSE Linux Enterprise Server 15 SP1-BCL | Fixed |
| SUSE Linux Enterprise Server 15 SP1-LTSS | Fixed |
| SUSE Linux Enterprise Server 15 SP2 | Fixed |
| SUSE Linux Enterprise Server 15 SP2-BCL | Fixed |
| SUSE Linux Enterprise Server 15 SP2-LTSS | Fixed |
| SUSE Linux Enterprise Server 15 SP3 | Fixed |
| SUSE Linux Enterprise Server 15 SP3-BCL | Fixed |
| SUSE Linux Enterprise Server 15 SP3-LTSS | Fixed |
| SUSE Linux Enterprise Server 15-LTSS | Fixed |
| SUSE Linux Enterprise Server for SAP Applications 15 | Fixed |
| SUSE Linux Enterprise Server for SAP Applications 15 SP1 | Fixed |
| SUSE Linux Enterprise Server for SAP Applications 15 SP2 | Fixed |
| SUSE Linux Enterprise Server for SAP Applications 15 SP3 | Fixed |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | Fixed |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | Fixed |
| SUSE Manager Proxy 4.0 | Fixed |
| SUSE Manager Proxy 4.1 | Fixed |
| SUSE Manager Proxy 4.2 | Fixed |
| SUSE Manager Retail Branch Server 4.0 | Fixed |
| SUSE Manager Retail Branch Server 4.1 | Fixed |
| SUSE Manager Retail Branch Server 4.2 | Fixed |
| SUSE Manager Server 4.0 | Fixed |
| SUSE Manager Server 4.1 | Fixed |
| SUSE Manager Server 4.2 | Fixed |
| openSUSE Leap 15.3 | Fixed |
| openSUSE Leap 15.4 | Fixed |
| openSUSE Leap 15.5 | Fixed |
| suse/nginx suse/rmt-nginx | Fixed |
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