Riskcovery

CVE-2026-56434

NGINX ngx_http_ssi_module vulnerability

State
Published
Severity
8.3 High
Published
Jul 15, 2026
Updated
Jul 15, 2026
Reserved
Jul 8, 2026

Read the record on cve.org

Description

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.

Scores

CVSSScoreVectorSource
4.08.3 HighCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:Nf5
3.16.5 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:Hf5

Weaknesses

Affected Products

ProductVersions
NGINX PlusF5
  • 37.0.0.1 to before 37.0.3.1Affected
  • R36 to before R36 P7Affected
  • R33 and laterAffected
NGINX Open SourceF5
  • 1.31.2 to before 1.31.3Affected
  • 0.8.11 to before 1.30.4Affected

References

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