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CVE-2025-53859

NGINX ngx_mail_smtp_module vulnerability

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in R34 P2, R33 P3, R32 P3, 1.29.1
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • F5 NGINX Plus

    From R34 · fixed in R34 P2; From R33 · fixed in R33 P3; From R32 · fixed in R32 P3; From R31; From R30

  • F5 NGINX Open Source

    From 0.7 · fixed in 1.29.1

References 1

my.f5.com