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
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. A compounding secondary behavior causes complete service translation failure when a maliciously crafted CLRP is deleted, enabling a denial-of-service condition against any targeted Service. No public exploit has been identified at time of analysis, and exploitation is constrained to users holding elevated cluster RBAC privileges; this is not confirmed actively exploited (CISA KEV).
Technical ContextAI
Cilium is an eBPF-based Kubernetes Container Network Interface (CNI) plugin that handles service load-balancing and network policy enforcement within Kubernetes clusters. CiliumLocalRedirectPolicy (CLRP) is a Cilium-specific custom resource that allows redirecting traffic destined for a Service's ClusterIP to a local pod endpoint, intended for use cases such as DNS proxying. The vulnerability arises because the addressMatcher field - which accepts arbitrary ClusterIPs - does not enforce the same namespace-scoping restrictions as serviceMatcher, creating an inconsistency in the policy evaluation engine. The affected package is pkg:go/github.com_cilium_cilium across multiple release branches. The root cause is classified as CWE-601 (Open Redirect), applied here at the network routing layer: Cilium's datapath can be instructed to forward service-bound traffic to attacker-controlled endpoints without restriction to the policy creator's namespace. The secondary corruption bug suggests that CLRP deletion triggers an inconsistent state update in Cilium's internal service map (likely the BPF map or kvstore-backed service state), causing translation entries to be invalidated without proper cleanup.
RemediationAI
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. The vendor explicitly states there is no workaround for this issue. As a compensating control pending upgrade, operators should audit and restrict RBAC permissions to create or modify CiliumLocalRedirectPolicy objects, limiting this right to highly trusted administrative principals only - note that this does not remediate the underlying bug but reduces the population of principals who can exploit it. Operators should also audit existing CiliumLocalRedirectPolicy objects for use of addressMatcher with ClusterIPs outside the policy creator's namespace. Patch PRs are referenced at https://github.com/cilium/cilium/pull/44584 and https://github.com/cilium/cilium/pull/44585 (note: a discrepancy exists between PR numbers cited in the advisory text versus the reference URLs - verify against the official advisory at https://github.com/cilium/cilium/security/advisories/GHSA-q6h5-q3q6-f87x before applying).
More in Open Redirect
View allA malicious third-party can give a crafted "ssh://..." URL to an unsuspecting victim, and an attempt to visit the URL ca
GFI Kerio Control versions 9.2.5 through 9.4.5 contain an HTTP response splitting vulnerability in the dest parameter of
PHP through 7.0.8 does not attempt to address RFC 3875 section 4.1.18 namespace conflicts and therefore does not protect
Multiple open redirect vulnerabilities in Apache Struts 2.0.0 through 2.3.15 allow remote attackers to redirect users to
Open redirect vulnerability in age-verification.php in the Age Verification plugin 0.4 and earlier for WordPress allows
Open redirect vulnerability in Kaseya Virtual System Administrator (VSA) 7.x before 7.0.0.29, 8.x before 8.0.0.18, 9.0 b
Vulnerability in the Oracle Applications Framework component of Oracle E-Business Suite (subcomponent: Popup windows (li
Unspecified vulnerability in the Oracle Application Server Single Sign-On component in Oracle Fusion Middleware 10.1.4.3
Flarum is open source discussion platform software. Rated medium severity (CVSS 6.5), this vulnerability is remotely exp
Open redirect vulnerability in Novius OS 5.0.1 (Elche) allows remote attackers to redirect users to arbitrary web sites
Open redirect vulnerability in the Redirect function in stageshow_redirect.php in the StageShow plugin before 5.0.9 for
Nteract v.0.28.0 was discovered to contain a remote code execution (RCE) vulnerability via the Markdown link. Rated crit
Vendor StatusVendor
SUSE
Severity: Moderate| Product | Status |
|---|---|
| SUSE Linux Enterprise Server 16.1 | Affected |
| SUSE Linux Enterprise Server for SAP applications 16.1 | Affected |
| SUSE Linux Enterprise Module for Package Hub 15 SP5 | Affected |
| SUSE Linux Enterprise Module for Package Hub 15 SP6 | Affected |
| openSUSE Leap 15.5 | Affected |
| openSUSE Leap 15.6 | Affected |
Share
External POC / Exploit Code
Leaving vuln.today