🛡️ CVE-2026-56434 — nginx

🟠 CVSS 8.0 — High ✅ No Known Exploit NVD
8.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

NGINX ngx_http_ssi_module vulnerability

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is high, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity low, availability high.

Affected software

CVE-2026-56434 is recorded against 6 packages.

  • nginx
  • nginx-gateway
  • nginx-gateway-fabric (from 2.0.0 up to 2.6.7)
  • nginx-ingress-controller
  • nginx-plus
  • waf (from 5.9.0 up to 5.13.4)

Timeline and source

Published on 20 July 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

my.f5.com (Web)
nvd.nist.gov (Web)

Details

Severity HIGH
CVSS Score 8.0
CVSS Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2026-07-20
Updated 2026-08-12
Modified 2026-07-20
Fix URL N/A

Affected Packages

Software From version Fixed in
nginx — —
nginx-gateway — —
nginx-gateway-fabric 2.0.0 2.6.7
nginx-ingress-controller — —
nginx-plus — —
waf 5.9.0 5.13.4

Site Security Check

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CVE-2026-56434 is rated CVSS 8.0 High. BotEraser scans your installation against known CVE records and tells you whether this vulnerability applies to the versions you actually run.

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