EUVD-2026-42101
GHSA-q6h5-q3q6-f87x
Severity by source
AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:N/A:H
Traffic hijacking to attacker-controlled pod enables full C:H and I:H; AV:A and PR:H reflect cluster-internal, privileged-RBAC prerequisites; S:C captures cross-namespace impact.
Primary rating from Vendor (https://github.com/cilium/cilium).
CVSS VectorVendor: https://github.com/cilium/cilium
CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:N/A:H
Lifecycle Timeline
1DescriptionCVE.org
Impact
Users with the ability to create CiliumLocalRedirectPolicies can specify arbitrary ClusterIPs via addressMatcher, which enables hijacking traffic to Services in any namespace, bypassing the namespace-scoping guarantees enforced by serviceMatcher.
In addition, deleting such a policy can corrupt Cilium's internal service state, causing service translation to stop working entirely for the affected Service.
Patches
This issue affects:
- Cilium v1.19.0 to v1.19.3 inclusive (fixed in PR #45584)
- Cilium v1.18.2 to v1.18.9 inclusive (fixed in PR #45585)
- All versions of Cilium prior to v1.17.16 (fixed in PR #45412)
This issue has been patched in:
- Cilium v1.19.4
- Cilium v1.18.10
- Cilium v1.17.16
Workarounds
There is no workaround to this issue.
Acknowledgements
The Cilium community has worked together with members of Isovalent to prepare these mitigations. Special thanks to @ysksuzuki for investigating and fixing the issue.
For more information
If there are any questions or comments about this advisory, please reach out on Slack.
To report potential vulnerabilities affecting Cilium, it strongly is encouraged to report them through the security mailing list at [security@cilium.io](mailto:security@cilium.io). This is a private mailing list for the Cilium security team, and reports will be treated as a top priority.
AnalysisAI
Traffic hijacking in Cilium's CiliumLocalRedirectPolicy (CLRP) mechanism allows a cluster user with RBAC permission to create CLRPs to specify arbitrary ClusterIPs via the addressMatcher field, redirecting service traffic across namespace boundaries and circumventing the namespace-scoping guarantees that serviceMatcher is designed to enforce. Affected versions span Cilium v1.17 (all prior to v1.17.16), v1.18.2-v1.18.9, and v1.19.0-v1.19.3. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the attacker to hold Kubernetes RBAC permission to create CiliumLocalRedirectPolicy custom resources - this is not granted by default in standard Kubernetes deployments and must be explicitly delegated. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 vector (AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:N/A:H) scores 6.9, reflecting two distinct risk dimensions: a cross-namespace traffic hijacking path (S:C) and a high-availability impact from state corruption (A:H). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | A Kubernetes tenant operator with RBAC permission to create CiliumLocalRedirectPolicy objects in their namespace crafts a CLRP using addressMatcher referencing the ClusterIP of a sensitive Service in another namespace (for example, a secrets management service or internal API gateway). Cilium's datapath redirects all traffic destined for that ClusterIP to a pod controlled by the attacker, enabling interception of cross-namespace service traffic. … |
| Remediation | The primary fix is to upgrade Cilium to a patched release: v1.19.4 for users on the v1.19 branch, v1.18.10 for users on the v1.18 branch, or v1.17.16 for users on the v1.17 branch. … Detailed patch versions, workarounds, and compensating controls in full report. |
Threat intelligence, references, and detailed analysis are available after sign-in.
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