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VulnerabilityPublished Updated

CVE-2026-4342: Kubernetes ingress-nginx · Improper Input Validation

Affects Kubernetes ingress-nginxSource CVE Database V5

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Not known to be exploited · CVSS 8.8 High · fixed in 1.15.1 : patch Kubernetes ingress-nginx soon.

Data as of 31 Oct 2026, 20:20 UTC

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
1.4% chance of exploitation in 30 days – higher than 73% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 1.15.1, 1.14.5, 1.13.9
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 19 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: evidence found.

    Public exploit code: GitHub proofs of concept

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), GitHub proofs of concept, the Metasploit, Exploit-DB and nuclei-templates index as of 31 Oct 2026.

What to do

Upgrade Kubernetes ingress-nginx to 1.15.1, 1.14.5 or 1.13.9.

Affected software

ProductAffectedFixed in
Kubernetesingress-nginxAffected
  • <1.13.9
  • <1.14.5
  • <1.15.1
Fixed in–
GitHubingress-nginxpkg:github/ingress-nginxOther threatsAffected
  • <1.13.9
  • <1.14.5
  • <1.15.1
Fixed in
  • 1.13.9
  • 1.14.5
  • 1.15.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate CVE-2026-4342, organizations should immediately update ingress-nginx controllers to the latest patched versions once available from the Kubernetes project or ingress-nginx maintainers. If you cannot patch yet, restrict network access to the ingress-nginx controller to trusted sources only, using network policies or firewall rules. Implement strict RBAC policies to limit which users or service accounts can create or modify Ingress resources and annotations, minimizing the risk of malicious configuration injection. Monitor ingress-nginx logs and Kubernetes audit logs for unusual annotation patterns or configuration changes. Consider deploying runtime security tools that can detect anomalous behavior or unauthorized code execution within the ingress-nginx pods. Additionally, review and minimize the cluster-wide Secret access granted to the ingress-nginx controller by following the principle of least privilege, potentially using Kubernetes Pod Security Policies or OPA Gatekeeper policies to enforce stricter access controls. Regularly back up Secrets and cluster configurations to enable recovery in case of compromise.

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.)

References

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