Cilium: Namespaced HTTPRoutes can redirect traffic to other namespaces
### Impact In 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. Gateway API functionality is disabled by default. ### Patches This issue affects: * Cilium v1.19 from v1.19.0 to v1.19.4 inclusive * Cilium v1.18 from v1.18.0 to v1.18.10 inclusive * All versions of Cilium before v1.17.17 This issue is patched in: * Cilium v1.19.5 * Cilium v1.18.11 * Cilium v1.17.17 ### Workarounds There 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. ### Acknowledgements The 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. ### For more information If you have any questions or comments about this advisory, please reach out on [Slack](https://docs.cilium.io/en/latest/community/community/). If 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 w
GHSA-w7c2-w76w-5hmj
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:GHSA-w7c2-w76w-5hmj
github.com/cilium/cilium
Source reference: /affected/0/package/name
- Affected versions
- Not stated in this record
- Fixed versions
- 1.17.17
Source reference:
/affected/0/ranges - Prerequisites
- Not stated in this record
github.com/cilium/ciliumCilium
Source reference: /affected/1/package/name
- Affected versions
- Not stated in this record
- Fixed versions
- 1.18.11
Source reference:
/affected/1/ranges - Prerequisites
- Not stated in this record
github.com/cilium/cilium
Source reference: /affected/2/package/name
- Affected versions
- Not stated in this record
- Fixed versions
- 1.19.5
Source reference:
/affected/2/ranges - Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"type": "SEMVER",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.17.17"
}
]
}
],
"package": {
"name": "github.com/cilium/cilium",
"purl": "pkg:golang/github.com/cilium/cilium",
"ecosystem": "Go"
},
"database_specific": {
"source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-w7c2-w76w-5hmj/GHSA-w7c2-w76w-5hmj.json"
}
},
{
"ranges": [
{
"type": "SEMVER",
"events": [
{
"introduced": "1.18.0"
},
{
"fixed": "1.18.11"
}
]
}
],
"package": {
"name": "github.com/cilium/ciliumCilium",
"purl": "pkg:golang/github.com/cilium/ciliumCilium",
"ecosystem": "Go"
},
"database_specific": {
"source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-w7c2-w76w-5hmj/GHSA-w7c2-w76w-5hmj.json"
}
},
{
"ranges": [
{
"type": "SEMVER",
"events": [
{
"introduced": "1.19.0"
},
{
"fixed": "1.19.5"
}
]
}
],
"package": {
"name": "github.com/cilium/cilium",
"purl": "pkg:golang/github.com/cilium/cilium",
"ecosystem": "Go"
},
"database_specific": {
"source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-w7c2-w76w-5hmj/GHSA-w7c2-w76w-5hmj.json"
}
}
]- Related CVEs
- CVE-2026-56742
Source reference:
/aliases
Publisher severity
No explicit severity was provided.
- Event
- #63967 · Revision 1
- Added to Heist Feed
- Publisher date