Overview
CVE-2025-64715 is a medium-severity vulnerability affecting Cilium, a networking, observability, and security solution that leverages an eBPF-based dataplane. This vulnerability impacts CiliumNetworkPolicys that utilize egress.toGroups.aws.securityGroupsIds. When these policies reference AWS security group IDs that are either non-existent or not attached to any network interface, they can unintentionally permit broader outbound access than intended by the policy author.
Technical Details
The vulnerability stems from the failure to generate the toCIDRset section of the derived Cilium network policy when the referenced AWS security group IDs are invalid or unattached. Without the toCIDRset constraints, outbound traffic may be permitted to a wider range of destinations than specified in the original policy. Specifically, if the referenced Security Group ID is not found, the expected CIDR restrictions are not enforced, potentially opening up unexpected egress pathways.
CVSS Analysis
The Common Vulnerability Scoring System (CVSS) score for CVE-2025-64715 is 4.0 (MEDIUM).
- Attack Vector (AV): Network (N)
- Attack Complexity (AC): High (H)
- Privileges Required (PR): Low (L)
- User Interaction (UI): None (N)
- Scope (S): Unchanged (U)
- Confidentiality Impact (C): None (N)
- Integrity Impact (I): Low (L)
- Availability Impact (A): None (N)
While the CVSS score is medium, the potential for unintended outbound traffic exposure should be carefully considered based on the specific network environment and security requirements.
Possible Impact
The impact of this vulnerability is that Cilium network policies may not function as intended, potentially leading to:
- Unintended Outbound Access: Applications may be able to communicate with destinations that they were not explicitly authorized to access.
- Security Policy Bypass: Established security policies may be bypassed, increasing the attack surface.
- Data Exfiltration: In some scenarios, this vulnerability could potentially be leveraged for data exfiltration, although this is less likely given the ‘Integrity Impact’ rating.
Mitigation and Patch Steps
The recommended mitigation is to upgrade to one of the following patched Cilium versions:
- Cilium version 1.16.17 or later
- Cilium version 1.17.10 or later
- Cilium version 1.18.4 or later
There are no known workarounds for this vulnerability. It is crucial to upgrade to a patched version to ensure proper enforcement of network policies.
