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Fencer Vulns
medium 6.5

CVE-2026-54462 json

knative.dev/pkg admission webhooks allow unbounded request-body memory exhaustion

published 2026-10-27 12 d ago modified 2026-11-05 3 d ago also GHSA-2hw4-c9m4-f2fj , GO-2026-6880 , EUVD-2026-111135

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

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.

Patch / fix

  • go knative.dev/pkg 0.0.0-20260531000007-52dbd5ece63f

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-54462 updated cvss 6.5

knative.dev/pkg: knative.dev/pkg: Denial of Service via oversized request body

  • Red Hat Builds for Red Hat OpenShift openshift-builds/openshift-builds-waiters-rhel9, openshift-builds/openshift-builds-webhook-rhel9, openshift-builds/openshift-builds-rhel9-operator, openshift-builds/openshift-builds-waiters-rhel10, openshift-builds/openshift-builds-webhook-rhel10, openshift-builds/openshift-builds-rhel10-operator, +8 more Red Hat Custom Metric Autoscaler operator for Red Hat Openshift custom-metrics-autoscaler/custom-metrics-autoscaler-rhel9, custom-metrics-autoscaler/custom-metrics-autoscaler-adapter-rhel9, custom-metrics-autoscaler/custom-metrics-autoscaler-rhel9-operator, custom-metrics-autoscaler/custom-metrics-autoscaler-admission-webhooks-rhel9, custom-metrics-autoscaler/custom-metrics-autoscaler-http-add-on-scaler-rhel9, custom-metrics-autoscaler/custom-metrics-autoscaler-http-add-on-operator-rhel9, +1 more Red Hat MCP Server for Red Hat OpenShift openshift-mcp/openshift-mcp-server-rhel9, openshift-mcp-tech-preview/openshift-mcp-server-rhel9 Red Hat OpenShift Lightspeed openshift-lightspeed/openshift-mcp-server-rhel9 Red Hat OpenShift Pipelines openshift-pipelines/pipelines-opc-rhel9, openshift-pipelines/pipelines-events-rhel8, openshift-pipelines/pipelines-events-rhel9, openshift-pipelines-client 1.15.3-11580.el8, openshift-pipelines/pipelines-cli-tkn-rhel8, openshift-pipelines/pipelines-cli-tkn-rhel9, +50 more Red Hat OpenShift Serverless kn-workflow-plugin 1.38.1-1.el9, openshift-serverless-1/kn-client-kn-rhel9, openshift-serverless-clients 1.17.0-4.el9, openshift-serverless-1/logic-rhel9-operator, openshift-serverless-1/kn-serving-queue-rhel9, openshift-serverless-1/net-istio-webhook-rhel9, +28 more
    +2 more products
    Red Hat OpenShift AI (RHOAI) rhoai/odh-maas-api-rhel9, rhoai/odh-kserve-agent-rhel9, rhoai/odh-kserve-router-rhel9, rhoai/odh-model-registry-rhel9, rhoai/odh-ta-lmes-driver-rhel9, rhoai/odh-maas-controller-rhel9, +11 more Red Hat OpenShift Container Platform 4 cri-o, openshift4/oc-mirror-plugin-rhel9, openshift4/ose-aws-ebs-csi-driver-rhel9
    affected: no fix available “Fix deferred”
  • Red Hat Openshift Data Foundation 4 odf4/mcg-cli-rhel9, odf4/odf-cli-rhel9, odf4/mcg-rhel9-operator
    affected: no fix available, no fix planned “Out of support scope”
  • Red Hat OpenShift Dev Spaces devspaces/udi-rhel9, devspaces/traefik-rhel9
    affected: no fix available “Fix deferred”
  • Red Hat OpenShift Virtualization 4 container-native-virtualization/kubevirt-ssp-operator-rhel9, container-native-virtualization/kubevirt-tekton-tasks-operator, container-native-virtualization/kubevirt-template-validator-rhel9, container-native-virtualization/kubevirt-tekton-tasks-operator-rhel9
    affected: no fix planned “Out of support scope”
  • Red Hat Trusted Artifact Signer rhtas/ec-rhel9, rhtas/policy-controller-rhel9 Red Hat Web Terminal web-terminal/web-terminal-tooling-rhel9
    affected: no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
6 d ago

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/knative/pkg/security/advisories/GHSA-2hw4-c9m4-f2fj referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
go knative.dev/pkg
<0.0.0-20260531000007-52dbd5ece63f
0.0.0-20260531000007-52dbd5ece63f

Affected products

  • knative pkg

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.