Assessment
Why it matters
EPSS is 3.5%; technical severity is CVSS 9.2.
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.
Who should care
- Teams operating Nginx Gateway Fabric, Nginx Ingress Controller, Nginx Plus +1 more
- Vulnerability and exposure management teams
- Security operations teams monitoring exploitation activity
Response plan
What I would do
- Confirm whether Nginx Gateway Fabric, Nginx Ingress Controller, Nginx Plus +1 more is present in the environment.
- Identify affected versions and establish whether vulnerable services are exposed or reachable.
- F5 Security advisory K000162097
- Review relevant security telemetry for evidence of attempted or successful exploitation.
- Document the remediation decision and track it to verified completion.
Treatment intelligence
Remediation intelligence
Vendor sources are listed before government and third-party guidance. Confirm product applicability and change prerequisites before deployment.
Technical details
- CVSS 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
- CWE
- CWE-122
- Affected versions
- F5 Nginx Gateway Fabric (Start Including 1.3.0, End Including 1.6.2 | Start Including 2.0.0, End Excluding 2.6.7); F5 Nginx Ingress Controller (Start Including 3.5.0, End Including 3.7.2 | Start Including 5.0.0, End Excluding 5.5.3 | Start Including 2026-lts-r1, End Excluding 2026-lts-r4 | Version 4.0.0); F5 Nginx Plus (Start Including 37.0.0.1, End Excluding 37.0.3.1 | Start Including r33, End Excluding r36 | Version r36 | Version r36); F5 Waf (Start Including 4.11.0, End Including 4.16.0 | Start Including 5.2.0, End Including 5.8.0 | Start Including 5.9.0, End Excluding 5.13.4)
- Fixed versions
- F5 Nginx Gateway Fabric (Fixed from 2.6.7); F5 Nginx Ingress Controller (Fixed from 5.5.3, 2026-lts-r4); F5 Nginx Plus (Fixed from 37.0.3.1, r36); F5 Waf (Fixed from 5.13.4)
- Published
- 15 July 2026
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
Signal timeline
- CVE published
- Latest EPSS score: 3.5%
- Signal calculated at 16