CVE-2026-56434

NameCVE-2026-56434
DescriptionNGINX 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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDSA-6496-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
nginx (PTS)bookworm, bookworm (security)1.22.1-9+deb12u9vulnerable
trixie1.26.3-3+deb13u7vulnerable
trixie (security)1.26.3-3+deb13u8fixed
forky, sid1.30.4-5fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
nginxsourcetrixie1.26.3-3+deb13u8DSA-6496-1
nginxsource(unstable)1.30.1-7

Notes

https://my.f5.com/manage/s/article/K000162098

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