A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and a string expression references the map's regex capture variables before referencing the map output variable. Alternatively, the same result could be achieved by using a non-cacheable variable in a string expression under certain conditions. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR.
Impact: This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. 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.
CVSS Details
- CVSS 4.0 Base Score: 9.2 (CRITICAL)
- CVSS 4.0 Vector: (CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)
- CVSS 3.1 Base Score: 8.1
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade nginx | Jul 21, 2026 | Jul 15, 2026 |
| Amazon Linux Ami 2 | — | Upgrade nginx-mod-http-xslt-filterUpgrade nginx-mod-mailUpgrade nginx-filesystemUpgrade nginx-debuginfoUpgrade nginx-mod-streamUpgrade nginx-mod-develUpgrade nginx-mod-http-geoipUpgrade nginx-coreUpgrade nginxUpgrade nginx-mod-http-perlUpgrade nginx-mod-http-image-filterUpgrade nginx-all-modules | Aug 5, 2026 | Aug 5, 2026 |
| Amazon_linux_2023 | — | Upgrade nginx-debuginfoUpgrade nginx-mod-http-perlUpgrade nginx-mod-mail-debuginfoUpgrade nginx-mod-http-image-filter-debuginfoUpgrade nginx-mod-streamUpgrade nginx-mod-http-image-filterUpgrade nginx-mod-develUpgrade nginx-coreUpgrade nginx-debugsourceUpgrade nginx-mod-http-perl-debuginfoUpgrade nginx-mod-http-xslt-filterUpgrade nginx-mod-stream-debuginfoUpgrade nginxUpgrade nginx-mod-mailUpgrade nginx-filesystemUpgrade nginx-core-debuginfoUpgrade nginx-mod-http-xslt-filter-debuginfoUpgrade nginx-all-modules | Aug 10, 2026 | Jul 15, 2026 |
| Debian | — | Upgrade nginx | Sep 21, 2026 | Jul 15, 2026 |
| Freebsd | — | Upgrade nginx-develUpgrade angieUpgrade nginx | Aug 3, 2026 | Aug 3, 2026 |
| Gentoo Linux | — | Upgrade www-servers/nginx. | Aug 17, 2026 | Aug 17, 2026 |
| Nginx | — | Upgrade to nginx version 1.31.3Upgrade to nginx version 1.30.4 | Jul 16, 2026 | Jul 15, 2026 |
| Redhat_linux | — | Upgrade nginx-core-debuginfoUpgrade nginx-mod-stream-debuginfoUpgrade nginx-mod-http-image-filter-debuginfoUpgrade nginx-mod-develUpgrade nginxUpgrade nginx-mod-http-xslt-filter-debuginfoUpgrade nginx-filesystemUpgrade nginx-mod-streamUpgrade nginx-mod-http-perl-debuginfoUpgrade nginx-all-modulesUpgrade nginx-mod-http-xslt-filterUpgrade nginx-mod-mailUpgrade nginx-mod-http-image-filterUpgrade nginx-debuginfoUpgrade nginx-debugsourceUpgrade nginx-mod-mail-debuginfoUpgrade nginx-mod-http-perlUpgrade nginx-core | Jul 20, 2026 | Jul 15, 2026 |
| Rocky_linux | — | Upgrade nginx-mod-mail-debuginfoUpgrade nginx-mod-streamUpgrade nginx-mod-mailUpgrade nginx-mod-http-perl-debuginfoUpgrade nginx-coreUpgrade nginx-mod-http-image-filter-debuginfoUpgrade nginx-debuginfoUpgrade nginx-mod-http-xslt-filterUpgrade nginx-mod-stream-debuginfoUpgrade nginx-debugsourceUpgrade nginx-mod-develUpgrade nginx-mod-http-perlUpgrade nginx-core-debuginfoUpgrade nginx-mod-http-image-filterUpgrade nginx-mod-http-xslt-filter-debuginfoUpgrade nginx | Sep 15, 2026 | Sep 11, 2026 |
| Ubuntu | — | Upgrade nginx-fullUpgrade nginx-extrasUpgrade nginxUpgrade nginx-coreUpgrade nginx-light | Jul 21, 2026 | Jul 20, 2026 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Aug 5, 2026 | Jul 15, 2026 |
Prioritise with Active Threat Intelligence
With curated Threat Intelligence, you can see which vulnerabilities truly put you at risk, prioritize what matters most, and act before attackers do.
Explore Intelligence Hub