CVE-2026-4342: kubernetes ingress-nginx Improper Input Validation
Vulnerability summary
CVE-2026-4342 is a high (CVSS 8.8) Improper Input Validation vulnerability in kubernetes ingress-nginx. EPSS estimates a 0.63% chance of exploitation in the next 30 days, higher than 49.1% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 2 · Related 2Timeline
- 19-03-2026PublishedVulnerability first disclosed.
- 21-03-2026Last modifiedVulnerability information updated.
Description
A security issue was discovered in ingress-nginx where a combination of Ingress annotations can be used to inject configuration into nginx. This can lead to arbitrary code execution in the context of the ingress-nginx controller, and disclosure of Secrets accessible to the controller. (Note that in the default installation, the controller can access all Secrets cluster-wide.)
CVSS metrics
3 scores · 3 sources · 1 version- OSV · GoEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- NVDNIST8.8HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.63%
Chance of exploitation in the next 30 days
Percentile
49%
Versus all other CVEs
30-day change
-0.87 pp
From 1.49% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Kubernetes2 products
- ingress-nginx< 1.13.9 | < 1.14.5 | < 1.15.1
- nginx_ingress_controller< 1.13.9 | ≥ 1.14.0, < 1.14.5 | 1.15.0
K8s.io1 product
- ingress-nginx< 0.0.0-20260319175635-5183b7d86137
2 vendors · 3 products
