GO-2026-6596Published

Cilium: Namespaced HTTPRoutes can redirect traffic to other namespaces

Collected exploitation and prediction evidence

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

cve-program · CVE-2026-56742

Published

Cilium is a networking, observability, and security solution. Prior to 1.17.17, 1.18.11, and 1.19.5, Cilium clusters using Gateway API allow users with permissions to create or update namespaced HTTPRoutes to mirror HTTP traffic to any Service in any namespace, bypassing the ReferenceGrant authorization mechanism. Gateway API functionality is disabled by default. This issue is fixed in versions 1.17.17, 1.18.11, and 1.19.5.

Source published: 15 Jul 2026 19:14:07 UTC
Source modified: 16 Jul 2026 12:57:08 UTC
Observed here: 23 Oct 2026 15:48:27 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 5.9 CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L

euvd · EUVD-2026-44773

Published

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: Jul 15, 2026, 7:14:07 PM

dateUpdated: Jul 16, 2026, 12:57:08 PM

Source published: Jul 15, 2026, 7:14:07 PM (timezone not stated)
Source modified: Jul 16, 2026, 12:57:08 PM (timezone not stated)
Observed here: 9 Nov 2026 13:14:35 UTC
Source terms: ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 5.9 CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L

nvd · CVE-2026-56742

Published

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Analyzed

Weakness classifications: CWE-862

Original publisher date fields

published: 2026-07-15T20:17:51.850

lastModified: 2026-07-17T17:48:48.260

1 source CPE criteria · context only

cpe:2.3:a:cilium:cilium:*:*:*:*:*:*:*:*

The original JSON retains the logical configuration operators, exclusions and version bounds.

Source published: 15 Jul 2026 20:17:51 UTC
Source modified: 17 Jul 2026 17:48:48 UTC
Observed here: 25 Oct 2026 14:19:10 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 5.9 CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L

CVSS 3.1 · [email protected] · Primary · 8.9 CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L

osv · GHSA-w7c2-w76w-5hmj

Published

### 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 [[email protected]](mailto:[email protected]). This is a private mailing list for the Cilium security team, and your report will be treated as top priority.

Source published: 24 Sep 2026 19:38:39 UTC
Source modified: 1 Oct 2026 20:56:11 UTC
Observed here: 24 Oct 2026 13:19:41 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L

Publisher rating · MODERATE

osv · GO-2026-6596

Published

Cilium: Namespaced HTTPRoutes can redirect traffic to other namespaces in github.com/cilium/cilium

Source published: 1 Oct 2026 20:23:38 UTC
Source modified: 7 Oct 2026 17:45:13 UTC
Observed here: 24 Oct 2026 13:19:41 UTC
Source terms: OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.