CVE-2026-54462: knative.dev/pkg admission webhooks allow unbounded request-body memory exhaustion
Knative pkg provides common packages shared across Knative repositories. Prior to 0.0.0-20260531000007-52dbd5ece63f, the knative.dev/pkg/webhook admissionHandler in webhook/admission.go decodes an attacker-supplied AdmissionReview through json.NewDecoder(io.TeeReader(r.Body, &bodyBuffer)) under an http.HandlerFunc without an http.MaxBytesReader or equivalent body-size limit. A pod-network client can send one oversized POST to an admission webhook, causing the decoder and bodyBuffer to retain amplified copies of the request until the controller pod exhausts memory and is OOM-killed. Every downstream consumer using the shared webhook server inherits the vulnerable behavior, including Knative, Tekton, KEDA, Sigstore policy-controller, and Kpack. For consumers configured with failurePolicy=Fail, loss of the controller can interrupt admission; with failurePolicy=Ignore, the affected webhook is unavailable while other admissions continue. This issue is fixed in version 0.0.0-20260531000007-52dbd5ece63f.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
knative.dev/pkgto a version that resolves this vulnerability.Fixed in 0.0.0-20260531000007-52dbd5ece63f
Event History
Frequently Asked Questions
Which deployments are exposed?
Any downstream consumer using the vulnerable shared knative.dev/pkg webhook server is exposed, including Knative, Tekton, KEDA, Sigstore policy-controller, and Kpack. The issue affects versions before 0.0.0-20260531000007-52dbd5ece63f.
What does an attacker need to exploit this issue?
An attacker needs pod-network access to send an oversized POST request to an affected admission webhook. No user interaction is required, and a single oversized request can exhaust controller-pod memory.
What is the operational effect of a successful attack?
The affected controller pod can be OOM-killed. If the webhook uses failurePolicy=Fail, admission operations can be interrupted; with failurePolicy=Ignore, that webhook becomes unavailable while other admissions continue.
What should be done if the affected component cannot be patched immediately?
The provided information identifies no temporary configuration mitigation. Prioritize updating the shared dependency to version 0.0.0-20260531000007-52dbd5ece63f or later, and account for the admission impact of the configured failurePolicy while remediation is pending.