What’s Vulnerable › Vulnerabilities

CVE-2026-54247: Skipper: Unbounded Request Body Read in Admission Webhook Causes Memory Exhaustion DoS

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-14 · updated 2026-09-16
• Weakness: CWE-770

Description

Skipper is an HTTP router and reverse proxy for service composition. Prior to 0.26.22, Handler in dataclients/kubernetes/admission/admission.go passes the body of requests to the Kubernetes admission endpoint at :9443/admission directly to io.ReadAll(r.Body) without a size limit. An attacker with in-cluster network access and a valid Kubernetes client certificate can send a very large body that causes unbounded memory allocation and an out-of-memory termination of the Skipper process. The disruption is limited to Ingress and RouteGroup admission rather than pod creation or unrelated admission controllers, and Kubernetes normally restarts the process. This issue is fixed in version 0.26.22.

Affected products

• zalando skipper: before 0.26.22

References

• https://github.com/zalando/skipper/commit/c3d156c6caaefecc9a46774c0f9c3c70b97160b4
• https://github.com/zalando/skipper/pull/4053
• https://github.com/zalando/skipper/releases/tag/v0.26.22
• https://github.com/zalando/skipper/security/advisories/GHSA-cwxq-rc9x-2jvv

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