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CVE-2026-56434

NGINX ngx_http_ssi_module vulnerability

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 37.0.3.1, R36 P7, 1.31.3, 1.30.4
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_ssi_module module. This vulnerability may exist when the Server-Side Includes (SSI), proxy_pass, and proxy_buffering off directives are configured. With this configuration, an unauthenticated attacker with man-in-the-middle (MITM) ability to control responses from an upstream server may be able to cause a use-after-free in the NGINX worker process. This issue may lead to limited modification of memory or a restart of the NGINX worker process. Impact: This vulnerability may allow remote attackers to have limited control to modify memory contents or restart the NGINX worker process. There is no control plane exposure; this is a data plane issue only. 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 37.0.0.1 · fixed in 37.0.3.1; From R36 · fixed in R36 P7; From R33

  • F5 NGINX Open Source

    From 1.31.2 · fixed in 1.31.3; From 0.8.11 · fixed in 1.30.4

References 1

my.f5.com