CVE-2026-44939: Rancher cluster import endpoint YAML injection runs attacker containers

Critical 9.4 EPSS 1.3%

Rancher Manager's cluster import endpoint /v3/import/{token}_{clusterId}.yaml renders the authImage query parameter into the generated manifest without sanitizing it, so URL-encoded newlines can inject arbitrary YAML. An attacker who has a cluster registration token and gets an operator to kubectl apply a crafted import URL deploys a DaemonSet on all control-plane nodes with hostNetwork, the cluster-admin cattle service account, /etc/kubernetes mounted from the host, and attacker-chosen commands, giving full control of the downstream cluster. SUSE Rancher rates it critical (CVSS 4.0 9.4).

CVE-2026-44939CVE identifier
9.4CVSS 4.0 base score (critical)
1.3%EPSS: chance of exploitation in the next 30 days (higher than 70% of CVEs)
2026-06-19published

What do these terms mean? CVE · CVSS score · exploited (KEV) · EPSS · backported fix · all terms

What to do now

Check whether you run the affected software and which version (commands below).
Install the fixed version for your system: see “Patch it” below.
The Helm upgrade rolls the Rancher pods; no node reboot needed. If compromise is suspected, rotate service accounts and credentials that may have been exposed.
If you cannot patch today, apply the temporary mitigation below and patch as soon as possible.

Affected and fixed versions

Affected:

Rancher 2.14.0 before 2.14.2
Rancher 2.13.0 before 2.13.6
Rancher 2.12.0 before 2.12.10
Rancher 2.11.0 before 2.11.14
Rancher 2.10.0 before 2.10.12

Fixed in:

Rancher v2.14.2
Rancher v2.13.6
Rancher v2.12.10
Rancher v2.11.14
Rancher v2.10.12

Am I affected?

helm list -n cattle-system
kubectl -n cattle-system get deploy rancher -o jsonpath='{.spec.template.spec.containers[0].image}{"\n"}'
# on each downstream cluster:
kubectl -n cattle-system get daemonset kube-api-auth -o yaml

Patch it

Use the commands for your system. Distribution packages often keep an older version number with the fix backported, so compare with the fixed package versions in the table below, not only with the upstream version.

Docker images

# Helm-installed Rancher (repo name as in your install, e.g. rancher-stable / rancher-latest)
helm repo update
helm get values rancher -n cattle-system -o yaml > values.yaml
helm upgrade rancher rancher-<CHART_REPO>/rancher \
  --namespace cattle-system \
  -f values.yaml \
  --version=2.14.2
# Community image on Docker Hub: rancher/rancher:v2.14.2 (the v2.13.6 / v2.12.10 / v2.11.14 / v2.10.12 tags are not on Docker Hub)

General update steps for every system are on the Linux and Unix & BSD pages; after updating, see which services to restart.

If you cannot patch yet

Before running kubectl apply on any import manifest URL, verify it comes from your Rancher server and matches the expected pattern (no extra or encoded query parameters).
Treat cluster registration tokens as secrets (do not paste them into docs, tickets or screenshots).

Look for signs of exploitation

SUSE Rancher: on downstream clusters inspect the kube-api-auth DaemonSet in the cattle-system namespace for unexpected command: or args: fields, non-standard container images, or modifications after the initial import; review cluster and deployment logs for malicious deployments.

Sources

Page generated automatically from official sources on 2026-11-03 18:05 UTC and reviewed by an editor. Always confirm with your vendor's advisory.