CVE-2026-56434
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.
Affected products
20- osv-coords18 versionspkg:apk/chainguard/commercial-nginx-pluspkg:apk/chainguard/nginx-mainlinepkg:apk/chainguard/nginx-stablepkg:apk/wolfi/nginx-mainlinepkg:apk/wolfi/nginx-stablepkg:bitnami/nginxpkg:bitnami/nginx-gatewaypkg:rpm/almalinux/nginxpkg:rpm/almalinux/nginx-all-modulespkg:rpm/almalinux/nginx-corepkg:rpm/almalinux/nginx-filesystempkg:rpm/almalinux/nginx-mod-develpkg:rpm/almalinux/nginx-mod-http-image-filterpkg:rpm/almalinux/nginx-mod-http-perlpkg:rpm/almalinux/nginx-mod-http-xslt-filterpkg:rpm/almalinux/nginx-mod-mailpkg:rpm/almalinux/nginx-mod-streampkg:rpm/opensuse/nginx&distro=openSUSE%20Tumbleweed
< 37.0.3.1-r0+ 17 more
- (no CPE)range: < 37.0.3.1-r0
- (no CPE)range: < 1.31.3-r0
- (no CPE)range: < 1.30.4-r0
- (no CPE)range: < 1.31.3-r0
- (no CPE)range: < 1.30.4-r0
- (no CPE)range: >= 0.8.11, < 1.30.4
- (no CPE)range: >= 0.8.11, < 1.30.4
- (no CPE)range: < 1:1.24.0-3.module_el8.10.0+4259+e9485ae5.4.alma.1
- (no CPE)range: < 1:1.24.0-3.module_el8.10.0+4259+e9485ae5.4.alma.1
- (no CPE)range: < 2:1.26.3-6.el10_2.6
- (no CPE)range: < 1:1.24.0-3.module_el8.10.0+4259+e9485ae5.4.alma.1
- (no CPE)range: < 1:1.24.0-3.module_el8.10.0+4259+e9485ae5.4.alma.1
- (no CPE)range: < 1:1.24.0-3.module_el8.10.0+4259+e9485ae5.4.alma.1
- (no CPE)range: < 1:1.24.0-3.module_el8.10.0+4259+e9485ae5.4.alma.1
- (no CPE)range: < 1:1.24.0-3.module_el8.10.0+4259+e9485ae5.4.alma.1
- (no CPE)range: < 1:1.24.0-3.module_el8.10.0+4259+e9485ae5.4.alma.1
- (no CPE)range: < 1:1.24.0-3.module_el8.10.0+4259+e9485ae5.4.alma.1
- (no CPE)range: < 1.31.3-1.1
Patches
Vulnerability mechanics
References
1- my.f5.com/manage/s/article/K000162098nvdVendor Advisory
News mentions
2- ⚡ Weekly Recap: WordPress RCE, SonicWall 0-Days, AI Service Attacks, SharePoint 0-Day and MoreThe Hacker News · Jul 20, 2026
- F5 Patches Multiple NGINX Vulnerabilities Enabling Heap Buffer Overflow and Code Execution AttacksCyber Security News · Jul 16, 2026