When NGINX Ingress Controller is configured with Custom Resource Definitions
High8.7CVE-2026-55723 · Published Jul 15, 2026 · updated Jul 16, 2026
When NGINX Ingress Controller is configured with Custom Resource Definitions (CRDs) or Ingress annotations, an injection vulnerability exists in the configuration generator of NGINX Ingress Controller. Multiple user-controllable fields are written into the generated NGINX configuration without sanitization. An authenticated attacker with permission to create or modify these CRDs or annotations may craft values that inject arbitrary NGINX configuration directives. Impact: An authenticated attacker granted write access to NGINX Ingress Controller CRDs or Ingress annotations through the Kubernetes API may be able to inject arbitrary NGINX configuration directives, create or delete files, or disable services. There is no data plane exposure; this is a control plane issue only. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Affected versions
| Package | Affected | Fixed in |
|---|---|---|
| NGINX Ingress Controller Product | >= 5.0.0, < 5.5.2 | 5.5.2 |
| >= 2026-lts-r1, < 2026-lts-r3 | 2026-lts-r3 |
Details and references
- CVSS 4.0
- CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/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
- Severity from
- the vendor (its own CVE record or advisory)
- Weakness
- CWE-76
More F5 advisories
All F5| Date | Advisory | Severity | Fixed in |
|---|---|---|---|
| Jul 15 | F5 NGINX: uninitialized resource | High8.8 | Plus 37.0.3.1+3 more |
| Jul 15 | F5 NGINX: path traversal | Medium5.3 | 2.47.0+1 more |
| Jul 15 | F5 NGINX Plus: out-of-bounds read | Medium6.3 | 37.0.3.1+1 more |
| Jul 15 | F5 BIG-IP: denial of service | High8.7 | 21.1.0.1+7 more |
| Jul 15 | F5 NGINX: use after free | High8.3 | Plus 37.0.3.1+3 more |
| Jul 15 | F5 NGINX Ingress Controller: denial of service | High7.1 | 5.5.2+1 more |