NGINX Ingress Controller vulnerability

published 2026-07-15 3 mo ago modified 2026-10-24 15 d ago also EUVD-2026-44680

cvss: 8.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits: 0; none known

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.

Patch / fix

fixed in 1 links 1

F5 NGINX Ingress Controller 5.5.2, 2026-lts-r3

my.f5.com/manage/s/article/K000161800 advisory

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 3 mo ago (2026-07-15)

Exploit prediction

0.51% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L
CNA	4.0	8.7	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
CNA	4.0	8.7	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

Affected products

F5 NGINX Ingress Controller

Classification

Weakness

CWE-76 Improper Neutralization of Equivalent Special Elements

References

my.f5.com /manage/s/article/K000161800
vendor-advisory, patch, mitigation

Sources

CVE List CVE-2026-55723
NVD CVE-2026-55723

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Summary