NTLM coercion via subPath symlinks on Windows Kubernetes nodes
Key facts
- Attack vector
- Network
- Privileges required
- High
- User interaction
- None
- Attack complexity
- High
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Partial Red Hat: 1 fixed, 1 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-59 and the CVSS impact.
Summary
Kubernetes from v1.34.0 through v1.34.11, from v1.35.0 through v1.35.8, from v1.36.0 through v1.36.4 and from v1.37.0 through v1.37.0 on Windows nodes is affected. The kubelet does not reject a subPath symlink that resolves to a UNC path (CWE-59), so it authenticates to an attacker-controlled network share. A remote attacker with high privileges obtains the NetNTLMv2 hash of the kubelet account, which can be cracked or relayed to impersonate the node.
Written with Claude Haiku 5.5 from the sources below · 2026-11-04
Description from the CNA
An NTLM coercion vulnerability exists on Windows nodes when the subPath supplied in a pod's volumeMounts is set to a symbolic link that points to an attacker-controlled network share. When a kubelet resolves symlinks, it does not reject a target that resolves to a UNC path. As a result, the kubelet will transparently attempt to authenticate to the share using NTLM. This allows an attacker to obtain the NetNTLMv2 hash of the account under which the kubelet is running. An attacker could then attempt to crack the hash to retrieve the corresponding password or relay it to impersonate the node, if the node is domain-joined.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Kubernetes | Kubernetes | v1.34.0 – v1.34.11; v1.35.0 – v1.35.8; v1.36.0 – v1.36.4; v1.37.0 – v1.37.0 | — | No fix listed | CNA |
- Kubernetes VendorKubernetes Affected v1.34.0 – v1.34.11; v1.35.0 – v1.35.8; v1.36.0 – v1.36.4; v1.37.0 – v1.37.0 Fixed in — No fix listed CNA
CPE names Threatist (inferred) · 1
Inferred from how NVD named this product before; not given by a source.
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:* | — | — | Kubernetes |
- cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:* Versions — — ·Kubernetes
Remediation
Red Hat fixes Red Hat OpenShift for Windows Containers 11.0 in RHSA-2026:94562, released 2026-11-03. The sources list no fixed version for Kubernetes. Red Hat lists Red Hat OpenShift for Windows Containers as affected with no plan available.
Written with Claude Haiku 5.5 from the sources below · 2026-11-04
Red Hat 1 advisory
- RHSA-2026:94562 Released 2026-11-03 · Red Hat rating CriticalRed Hat OpenShift for Windows Containers 11.0 product release
- Red Hat OpenShift for Windows Containers 11.0 registry.redhat.io/openshift4-wincw/windows-machine-config-rhel9-operator
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat OpenShift for Windows Containers | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift for Windows Containers 11.0 | Fixed | RHSA-2026:94562 |
Not affected: 1 product
- Red Hat OpenShift for Windows Containers 11.0
Timeline
- 2026-10-26 Threatist record created from CVE-2026-76654
- 2026-10-27 Alias added: GHSA-fvcc-576m-9wv4
- 2026-10-27 Priority changed: MEDIUM → LOW
- 2026-11-03 CISA SSVC decision points changed
- 2026-11-04 Fix available: RHSA-2026:94562 · Red Hat
- 2026-11-04 Fix available: Red Hat OpenShift for Windows Containers 11.0 · Red Hat
References
More Kubernetes vulnerabilities
- TI-2025-01719 ingress-nginx admission controller RCE escalation CVSS 3.1CRITICAL 9.8
- TI-2018-16130 Improper privilege management in Kubernetes CVSS 3.0CRITICAL 9.8
- TI-2025-00932 ingress-nginx controller - configuration injection via unsanitized mirror annotations CVSS 3.1HIGH 8.8
- TI-2019-08418 Kubernetes kubelet exposes /debug/pprof info on healthz port CVSS 3.1HIGH 8.2
- TI-2026-02839 ingress-nginx rewrite-target nginx configuration injection CVSS 3.1HIGH 8.8
- TI-2025-18233 ingress-nginx controller - configuration injection via unsanitized auth-url annotation CVSS 3.1HIGH 8.8
Sources
- CVE-2026-76654 · CVE Program
- CVE-2026-76654 · NVD
- FIRST EPSS
- GHSA-fvcc-576m-9wv4 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-76654 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences