Medium [CVE-2026-13318] SSRF in virt-api port-forward via unvalidated guest-agent-reported IP
This medium-severity Red Hat Linux advisory covers CVE-2026-13318 affecting Red Hat OpenShift Virtualization 4.
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Summary
A server-side request forgery (SSRF) flaw was found in KubeVirt's virt-api port-forward handler. When processing a port-forward request to a VirtualMachineInstance (VMI), virt-api reads the target IP from vmi.
Status. Interfaces[0].IP and passes it directly to net.
Dial() without validation.
For VMIs using non-masquerade network bindings (bridge or secondary-only), this IP is reported by the QEMU guest agent running inside the VM and is fully controllable by the VM owner.
An attacker with kubevirt.io:edit permissions can create a VM with a modified guest agent that reports an arbitrary IP address, then request port-forward to establish a bidirectional TCP tunnel from virt-api's cluster-internal network position to any routable destination, bypassing NetworkPolicy isolation. Red Hat has rated this issue as Moderate impact.
Only VMs configured with bridge binding or secondary-only network interfaces (which require a cluster administrator to have created a NetworkAttachmentDefinition) are affected. Red Hat severity: Moderate — CVSS 6.4 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N).
Weakness: CWE-918. Affected Red Hat products: Red Hat OpenShift Virtualization 4.
Red Hat does not currently list a fixing RHSA for this CVE.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 14 days ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 14 days ago·verify at source
Mitigation checklist
- Users who do not use bridge binding or secondary-only network interfaces for their VMs are not affected by this vulnerability. For environments using these configurations, cluster administrators can apply egress NetworkPolicy to the openshift-cnv namespace to restrict virt-api's outbound connections to known-legitimate destinations (launcher pod CIDRs and node IPs), which blocks the SSRF to arbitrary targets.
Official advisory · high-confidence parse· fetched 14 days ago·verify at source
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