Heap-based buffer overflow in NGINX Plus and NGINX Open Source - CVE-2026-27654

Vulnerability identifier: #VU124478

CSH Severity: Medium

CVSS v4: 8.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-27654

CWE-ID: CWE-122

Exploitation vector: Remote access

Exploit availability: Public exploit is available

The vulnerability allows a remote attacker to perform a denial of service attack.

The vulnerability exists due to a boundary error in the ngx_http_dav_module module. A remote attacker can send specially crafted request to the server, trigger a heap-based buffer overflow and perform a denial of service attack or modify source or destination file names outside the document root. 

NGINX Plus
NGINX Open Source
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server 15 SP5
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 Server 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Real Time 15
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux Server - AUS
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Red Hat CodeReady Linux Builder for x86_64 - Extended Update Support
Red Hat CodeReady Linux Builder for Power, little endian - Extended Update Support
Red Hat CodeReady Linux Builder for IBM z Systems - Extended Update Support
Red Hat CodeReady Linux Builder for ARM 64 - Extended Update Support
Ubuntu
Server Applications Module
openSUSE Leap
openEuler
Anolis OS
Fedora
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
nginx-mod-vts
nginx-mod-fancyindex
nginx-mod-headers-more
nginx-mod-brotli
nginx-mod-modsecurity
nginx (Ubuntu package)
nginx-mod-naxsi
nginx (Red Hat package)
nginx-debugsource
nginx-source
nginx-debuginfo
nginx
nginx-mod-devel
nginx-help
nginx-filesystem
nginx-all-modules
nginx-mod-stream
nginx-mod-mail
nginx-mod-http-xslt-filter
nginx-mod-http-perl
nginx-mod-http-image-filter
nginx-doc
nginx-core

Install updates from vendor's website.

NGINX Plus - addressed in versions R32 P5, R35 P2, R36 P3
NGINX Open Source - addressed in versions 1.28.3, 1.29.7
nginx-mod-vts - update to 0.2.4-7.fc44
nginx-mod-fancyindex - update to 0.6.0-2.fc44
nginx-mod-headers-more - update to 0.39-7.fc44
nginx-mod-brotli - update to 1.0.0~rc-7.fc44
nginx-mod-modsecurity - update to 1.0.4-8.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
nginx-mod-naxsi - update to 1.6-15.fc44
nginx (Red Hat package) - addressed in versions 1.20.1-10.el9_0.3, 1.20.1-14.el9_2.5, 1.20.1-16.el9_4.5, 1.20.1-24.el9_7.2, 1.26.3-1.el10_0.8, 1.26.3-2.el10_1.1
nginx-debugsource - addressed in versions 1.21.5-150400.3.15.1, 1.21.5-150600.10.15.1
nginx-source - addressed in versions 1.21.5-150400.3.15.1, 1.21.5-150600.10.15.1
nginx-debuginfo - addressed in versions 1.21.5-150400.3.15.1, 1.21.5-150600.10.15.1
nginx - addressed in versions 1.21.5-150400.3.15.1, 1.21.5-150600.10.15.1
nginx-mod-devel - update to 1.24.0-8
nginx-help - update to 1.24.0-8
nginx-filesystem - update to 1.24.0-8
nginx-all-modules - update to 1.24.0-8
nginx-mod-stream - update to 1.24.0-8
nginx-mod-mail - update to 1.24.0-8
nginx-mod-http-xslt-filter - update to 1.24.0-8
nginx-mod-http-perl - update to 1.24.0-8
nginx-mod-http-image-filter - update to 1.24.0-8
nginx-debugsource - update to 1.24.0-8
nginx-debuginfo - update to 1.24.0-8
nginx - update to 1.24.0-8
nginx - update to 1.26.2-5
nginx-filesystem - update to 1.26.2-5
nginx-doc - update to 1.26.2-5
nginx-all-modules - update to 1.26.2-5
nginx-mod-stream - update to 1.26.2-5
nginx-mod-mail - update to 1.26.2-5
nginx-mod-http-xslt-filter - update to 1.26.2-5
nginx-mod-http-perl - update to 1.26.2-5
nginx-mod-http-image-filter - update to 1.26.2-5
nginx-mod-devel - update to 1.26.2-5
nginx-core - update to 1.26.2-5
nginx - update to 1.28.3-1.fc44

• Exploit #12743 - CVE-2026-27654 (NGINX `ngx_http_dav_module` Heap Buffer Overflow via `size_t` Underflow (Remote DoS / Potential RCE)) (May 22, 2026)

• https://my.f5.com/manage/s/article/K000160382

• Multiple vulnerabilities in NGINX Open Source and NGINX Plus
• Fedora 44 update for nginx, nginx-mod-brotli, nginx-mod-fancyindex, nginx-mod-headers-more, nginx-mod-modsecurity, nginx-mod-naxsi, nginx-mod-vts
• Anolis OS update for nginx
• Red Hat Enterprise Linux 10 update for nginx
• Red Hat Enterprise Linux 8 update for the nginx:1.24 module
• Red Hat Enterprise Linux 9 update for the nginx:1.24 module
• Red Hat Enterprise Linux 9 update for nginx
• Red Hat Enterprise Linux 9 update for the nginx:1.26 module
• openEuler update for nginx
• Red Hat Enterprise Linux 10 update for nginx
• Red Hat Enterprise Linux 9 update for nginx
• Red Hat Enterprise Linux 9 update for nginx
• SUSE update for nginx
• Red Hat Enterprise Linux 9 update for nginx
• Red Hat Enterprise Linux 9 update for the nginx:1.24 module
• Red Hat Enterprise Linux 9 update for the nginx:1.24 module
• Red Hat Enterprise Linux 9 update for the nginx:1.26 module
• SUSE update for nginx
• Ubuntu update for nginx