Vulnerability · Published Oct 14, 2026 · Assigned by f5
CVE-2026-93479NGINX map directive and regex matching vulnerability
High 8.1
In plain English
A high-severity heap buffer overflow in NGINX Open Source from F5. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.2% (higher than 68% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and the root directive or access log format 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.24 | nginx | 1.30.6-r0 | ALPINE-CVE-2026-93479 |
| Debian:12 | nginx | no fix listed | DEBIAN-CVE-2026-93479 |
| Debian:13 | nginx | 1.26.3-3+deb13u10 | DEBIAN-CVE-2026-93479 |
| Debian:14 | nginx | 1.30.4-8 | DEBIAN-CVE-2026-93479 |
| Ubuntu:22.04:LTS | nginx | 1.18.0-6ubuntu14.22 | UBUNTU-CVE-2026-93479 |
| Ubuntu:22.04:LTS | nginx | 1.18.0-6ubuntu14.22 | USN-8955-1 |
| Ubuntu:24.04:LTS | nginx | 1.24.0-2ubuntu7.19 | USN-8955-1 |
| Ubuntu:24.04:LTS | nginx | 1.24.0-2ubuntu7.19 | UBUNTU-CVE-2026-93479 |
| Ubuntu:26.04:LTS | nginx | 1.28.3-2ubuntu1.12 | USN-8955-1 |
| Ubuntu:26.04:LTS | nginx | 1.28.3-2ubuntu1.12 | UBUNTU-CVE-2026-93479 |
| Ubuntu:26.10 | nginx | 1.30.4-7ubuntu1.1 | USN-8955-1 |
| Ubuntu:26.10 | nginx | 1.30.4-7ubuntu1.1 | UBUNTU-CVE-2026-93479 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| F5 | NGINX Plus | 37.1.0 – before 37.1.0.137.0.0 – before 37.0.5.1R36 – before *R35 – before *R34 – before *R33 – before * |
| F5 | NGINX Open Source | 1.31.2 – before 1.31.71.30.0 – before 1.30.6 |
Weakness: CWE-122 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- https://my.f5.com/manage/s/article/K000162607 vendor-advisory