CVE-2026-56434

CVE CVE-2026-56434EUVD EUVD-2026-44684Published 2026-07-15T14:33:46.000ZLast changed 2026-07-15T18:10:54.000ZCVSS 8.3

What the advisory describes

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.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

F5 — NGINX Open Source 0.8.11 <1.30.4; 1.31.2 <1.31.3
F5 — NGINX Plus R33 <*; 37.0.0.1 <37.0.3.1; R36 <R36 P7

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.

F5 — NGINX Open Source
F5 — NGINX Plus

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