Vulnerabilities in pkg:golang/github.com/cilium/ciliumCilium
PACKAGECVE-2026-56742 is a MODERATE (CVSS 5.9) namespaced httproutes can redirect traffic vulnerability (CWE-862: Missing Authorization) affecting Cilium libraries in the Go ecosystem. The issue involves namespaced httproutes can redirect traffic to other namespaces. Remediation is available by upgrading affected packages to version 1.17.17, 1.18.11, 1.19.5.
pkg:golang/github.com/cilium/ciliumCilium
Vulnerability advisories affecting package pkg:golang/github.com/cilium/ciliumCilium. Select an advisory below to view technical details or fixes.
| Advisory ID | CVE / NVD | Severity | Summary |
|---|---|---|---|
| GHSA-w7c2-w76w-5hmj | CVE-2026-56742 | MODERATE | Cilium: Namespaced HTTPRoutes can redirect traffic to other namespaces |
CVE-2026-56742 at a Glance
Security Impact
CVSS: 5.9
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L).
How to Fix CVE-2026-56742
To remediate this vulnerability, upgrade all affected Cilium dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade github.com/cilium/cilium to 1.17.17
Upgrade github.com/cilium/ciliumCilium to 1.18.11
Upgrade github.com/cilium/cilium to 1.19.5
Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for github.com/cilium/cilium
How to Check if You Are Affected
To determine whether your application is affected by CVE-2026-56742, inspect your project dependencies for Cilium:
inspect dependencies for github.com/cilium/cilium
Analyze the terminal output to locate any version of Cilium in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.17.17), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-862: Missing Authorization, where the product does not perform an authorization check when an actor attempts to access a resource or perform an action. In Cilium, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-56742 Affected Cilium Versions
3 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
github.com/cilium/cilium
|
Go |
< 1.17.17
|
1.17.17
|
|
github.com/cilium/ciliumCilium
|
Go |
≥ 1.18.0
< 1.18.11
|
1.18.11
|
|
github.com/cilium/cilium
|
Go |
≥ 1.19.0
< 1.19.5
|
1.19.5
|
References
Frequently Asked Questions
What is CVE-2026-56742?
Which Cilium versions are affected?
What version fixes CVE-2026-56742?
Is github.com/cilium/cilium affected?
Is github.com/cilium/ciliumCilium affected?
What is the CVSS score of CVE-2026-56742?
What CWE is associated with CVE-2026-56742?
How can I check Go dependencies for CVE-2026-56742?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-w7c2-w76w-5hmj",
"modified" : "2026-09-24T19:38:39Z",
"published" : "2026-09-24T19:38:39Z",
"aliases" : [ "CVE-2026-56742" ],
"summary" : "Cilium: Namespaced HTTPRoutes can redirect traffic to other namespaces",
"details" : "### Impact\n\nIn Cilium clusters using [Gateway API](https://docs.cilium.io/en/stable/network/servicemesh/gateway-api/gateway-api/), users with permissions to create or update namespaced HTTPRoutes can mirror HTTP traffic to any Service in any namespace, bypassing the ReferenceGrant authorization mechanism.\n\nGateway API functionality is disabled by default.\n\n### Patches\n\nThis issue affects:\n\n* Cilium v1.19 from v1.19.0 to v1.19.4 inclusive\n* Cilium v1.18 from v1.18.0 to v1.18.10 inclusive\n* All versions of Cilium before v1.17.17\n\nThis issue is patched in:\n\n* Cilium v1.19.5\n* Cilium v1.18.11\n* Cilium v1.17.17\n\n### Workarounds\n\nThere is no workaround to this issue. Users of this feature who are unable to upgrade can mitigate the risk by ensuring that RBAC permissions to create `HTTPRoute` objects are only granted to cluster admins.\n\n### Acknowledgements\n\nThe Cilium community has worked together with members of Isovalent to prepare these mitigations. Special thanks to @galanko for reporting the issue and @mhofstetter for their work on triaging and remediating this issue.\n\n### For more information\n\nIf you have any questions or comments about this advisory, please reach out on [Slack](https://docs.cilium.io/en/latest/community/community/).\n\nIf you think you have found a vulnerability affecting Cilium, we strongly encourage you to report it to our security mailing list at [security@cilium.io](mailto:security@cilium.io). This is a private mailing list for the Cilium security team, and your report will be treated as top priority.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/cilium/cilium"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "1.17.17"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/cilium/ciliumCilium"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "1.18.0"
}, {
"fixed" : "1.18.11"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/cilium/cilium"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "1.19.0"
}, {
"fixed" : "1.19.5"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/cilium/cilium/security/advisories/GHSA-w7c2-w76w-5hmj"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-56742"
}, {
"type" : "WEB",
"url" : "https://github.com/cilium/cilium/commit/7422068aff67ac77c7dcc57aa5b9240c91333deb"
}, {
"type" : "WEB",
"url" : "https://github.com/cilium/cilium/commit/e0b1cef513ff910323f3743e9f3e3d86721e4857"
}, {
"type" : "WEB",
"url" : "https://github.com/cilium/cilium/commit/f23929cff682d6ed0dc158070812cb302fc0032b"
}, {
"type" : "WEB",
"url" : "https://github.com/cilium/cilium/commit/fd47963ea394d5e8fa4a88c40a79063430c512ca"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/cilium/cilium"
}, {
"type" : "WEB",
"url" : "https://github.com/cilium/cilium/releases/tag/v1.17.17"
}, {
"type" : "WEB",
"url" : "https://github.com/cilium/cilium/releases/tag/v1.18.11"
}, {
"type" : "WEB",
"url" : "https://github.com/cilium/cilium/releases/tag/v1.19.5"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-862" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2026-09-24T19:38:39Z",
"nvd_published_at" : "2026-07-15T20:17:51Z"
}
}