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-filesystemUpgrade nginx-mod-http-xslt-filterUpgrade nginx-debuginfoUpgrade nginx-mod-mailUpgrade nginxUpgrade nginx-mod-http-image-filterUpgrade nginx-coreUpgrade nginx-mod-develUpgrade nginx-mod-http-perlUpgrade nginx-mod-streamUpgrade nginx-all-modulesUpgrade nginx-mod-http-geoip | Aug 5, 2026 | Aug 5, 2026 |
| Amazon_linux_2023 | — | Upgrade nginx-mod-stream-debuginfoUpgrade nginx-mod-mail-debuginfoUpgrade nginx-coreUpgrade nginx-mod-http-image-filterUpgrade nginx-mod-http-xslt-filterUpgrade nginx-mod-http-image-filter-debuginfoUpgrade nginx-debugsourceUpgrade nginx-mod-streamUpgrade nginx-mod-http-perl-debuginfoUpgrade nginx-mod-develUpgrade nginx-mod-http-perlUpgrade nginx-debuginfoUpgrade nginx-all-modulesUpgrade nginx-mod-http-xslt-filter-debuginfoUpgrade nginxUpgrade nginx-core-debuginfoUpgrade nginx-mod-mailUpgrade nginx-filesystem | 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-mod-stream-debuginfoUpgrade nginx-mod-http-xslt-filter-debuginfoUpgrade nginx-mod-http-image-filter-debuginfoUpgrade nginx-mod-streamUpgrade nginx-mod-develUpgrade nginxUpgrade nginx-core-debuginfoUpgrade nginx-filesystemUpgrade nginx-mod-mailUpgrade nginx-mod-http-xslt-filterUpgrade nginx-debuginfoUpgrade nginx-all-modulesUpgrade nginx-coreUpgrade nginx-mod-http-perlUpgrade nginx-mod-http-image-filterUpgrade nginx-debugsourceUpgrade nginx-mod-http-perl-debuginfoUpgrade nginx-mod-mail-debuginfo | Jul 20, 2026 | Jul 15, 2026 |
| Rocky_linux | — | Upgrade nginx-mod-develUpgrade nginxUpgrade nginx-mod-http-perlUpgrade nginx-core-debuginfoUpgrade nginx-mod-http-xslt-filter-debuginfoUpgrade nginx-mod-http-image-filterUpgrade nginx-mod-mailUpgrade nginx-mod-streamUpgrade nginx-debuginfoUpgrade nginx-coreUpgrade nginx-mod-mail-debuginfoUpgrade nginx-mod-http-image-filter-debuginfoUpgrade nginx-mod-http-perl-debuginfoUpgrade nginx-mod-stream-debuginfoUpgrade nginx-debugsourceUpgrade nginx-mod-http-xslt-filter | Sep 15, 2026 | Sep 11, 2026 |
| Ubuntu | — | Upgrade nginx-fullUpgrade nginxUpgrade nginx-extrasUpgrade 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 |
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