Uncontrolled Memory Allocation in NGINX Plus and NGINX Open Source - CVE-2026-42946

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Main Vulnerability Database Vulnerabilities #VU131375

Uncontrolled Memory Allocation in NGINX Plus and NGINX Open Source - CVE-2026-42946

Published: May 14, 2026


Vulnerability identifier: #VU131375
CSH Severity: Medium
CVSS v4: 8.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-42946
CWE-ID: CWE-789
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to disclose memory contents of the NGINX worker process or cause a denial of service.

The vulnerability exists due to memory allocation with excessive size value and use of out-of-range pointer offset in the ngx_http_scgi_module and ngx_http_uwsgi_module modules when processing responses from an upstream server via scgi_pass or uwsgi_pass. A remote attacker can control responses from an upstream server to disclose memory contents of the NGINX worker process or cause a denial of service.

Exploitation requires man-in-the-middle ability to control responses from an upstream server. There is no control plane exposure; this is a data plane issue only.


Affected software

NGINX Plus
NGINX Open Source
Gentoo Linux
Debian Linux
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Real Time 15
Ubuntu
Server Applications Module
openSUSE Leap
openEuler
Anolis OS
Fedora
nginx-mod-js-challenge
nginx-mod-vts
nginx-mod-fancyindex
nginx-mod-headers-more
nginx-mod-brotli
nginx-mod-modsecurity
nginx (Ubuntu package)
nginx-mod-naxsi
nginx
nginx-debuginfo
nginx-debugsource
nginx-mod-devel
nginx-mod-http-image-filter
nginx-mod-http-perl
nginx-mod-mail
nginx-mod-stream
nginx-all-modules
nginx-filesystem
nginx-mod-http-xslt-filter
nginx-help
nginx-source
nginx (Debian package)
compat-nginx
compat-nginx-debuginfo
compat-nginx-debugsource
compat-nginx-mod-http-image-filter
compat-nginx-mod-http-perl
compat-nginx-mod-http-xslt-filter
compat-nginx-mod-mail
compat-nginx-mod-stream
compat-nginx-all-modules
compat-nginx-filesystem
compat-nginx-help
nginx-core
nginx-doc
www-servers/nginx

How to mitigate CVE-2026-42946

Install security update from vendor's website.

NGINX Plus - addressed in versions R32 P6, R36 P4
NGINX Open Source - update to 1.30.1
nginx-mod-js-challenge - update to 0^20230517.gitda6852d-7.fc44
nginx-mod-vts - addressed in versions 0.2.4-9.fc42, 0.2.4-9.fc43, 0.2.4-9.fc44
nginx-mod-fancyindex - addressed in versions 0.6.0-4.fc42, 0.6.0-4.fc43, 0.6.0-4.fc44
nginx-mod-headers-more - addressed in versions 0.39-9.fc42, 0.39-9.fc43, 0.39-9.fc44
nginx-mod-brotli - addressed in versions 1.0.0~rc-9.fc42, 1.0.0~rc-9.fc43, 1.0.0~rc-9.fc44
nginx-mod-modsecurity - addressed in versions 1.0.4-10.fc42, 1.0.4-10.fc43, 1.0.4-10.fc44
nginx (Ubuntu package) - addressed in versions 1.4.6-1ubuntu3.9+esm6, 1.10.3-0ubuntu0.16.04.5+esm7, 1.14.0-0ubuntu1.11+esm2, 1.18.0-0ubuntu1.7+esm1, 1.18.0-6ubuntu14.12, 1.24.0-2ubuntu7.9, 1.28.0-6ubuntu1.4, 1.28.3-2ubuntu1.2
nginx-mod-naxsi - addressed in versions 1.6-17.fc42, 1.6-17.fc43, 1.6-17.fc44
nginx - addressed in versions 1.21.5-12, 1.21.5-14, 1.24.0-10
nginx-debuginfo - addressed in versions 1.21.5-12, 1.21.5-14, 1.24.0-10
nginx-debugsource - addressed in versions 1.21.5-12, 1.21.5-14, 1.24.0-10
nginx-mod-devel - addressed in versions 1.21.5-12, 1.21.5-14, 1.24.0-10
nginx-mod-http-image-filter - addressed in versions 1.21.5-12, 1.21.5-14, 1.24.0-10
nginx-mod-http-perl - addressed in versions 1.21.5-12, 1.21.5-14, 1.24.0-10
nginx-mod-mail - addressed in versions 1.21.5-12, 1.21.5-14, 1.24.0-10
nginx-mod-stream - addressed in versions 1.21.5-12, 1.21.5-14, 1.24.0-10
nginx-all-modules - addressed in versions 1.21.5-12, 1.21.5-14, 1.24.0-10
nginx-filesystem - addressed in versions 1.21.5-12, 1.21.5-14, 1.24.0-10
nginx-mod-http-xslt-filter - addressed in versions 1.21.5-12, 1.21.5-14, 1.24.0-10
nginx-help - addressed in versions 1.21.5-14, 1.24.0-10
nginx-debuginfo - addressed in versions 1.21.5-150400.3.20.1, 1.21.5-150600.10.18.1
nginx - addressed in versions 1.21.5-150400.3.20.1, 1.21.5-150600.10.18.1
nginx-debugsource - addressed in versions 1.21.5-150400.3.20.1, 1.21.5-150600.10.18.1
nginx-source - addressed in versions 1.21.5-150400.3.20.1, 1.21.5-150600.10.18.1
nginx (Debian package) - addressed in versions 1.22.1-9+deb12u7, 1.22.1-9+deb12u8, 1.26.3-3+deb13u5, 1.26.3-3+deb13u6
compat-nginx - update to 1.24.0-10
compat-nginx-debuginfo - update to 1.24.0-10
compat-nginx-debugsource - update to 1.24.0-10
compat-nginx-mod-http-image-filter - update to 1.24.0-10
compat-nginx-mod-http-perl - update to 1.24.0-10
compat-nginx-mod-http-xslt-filter - update to 1.24.0-10
compat-nginx-mod-mail - update to 1.24.0-10
compat-nginx-mod-stream - update to 1.24.0-10
compat-nginx-all-modules - update to 1.24.0-10
compat-nginx-filesystem - update to 1.24.0-10
compat-nginx-help - update to 1.24.0-10
nginx-mod-http-xslt-filter - update to 1.26.2-10
nginx - update to 1.26.2-10
nginx-mod-http-perl - update to 1.26.2-10
nginx-core - update to 1.26.2-10
nginx-mod-devel - update to 1.26.2-10
nginx-mod-http-image-filter - update to 1.26.2-10
nginx-filesystem - update to 1.26.2-10
nginx-doc - update to 1.26.2-10
nginx-all-modules - update to 1.26.2-10
nginx-mod-stream - update to 1.26.2-10
nginx-mod-mail - update to 1.26.2-10
nginx - addressed in versions 1.30.1-1.fc42, 1.30.1-1.fc43, 1.30.1-1.fc44
www-servers/nginx - update to 1.31.3-r1

External References

Related Security Bulletins