Read the docs
TI-2026-40915 Aliases CVE-2026-56742GHSA-w7c2-w76w-5hmj

Cilium: Namespaced HTTPRoutes can redirect traffic to other namespaces

Priority LOW 38CWE-862Published · Updated

Key facts

Attack vector
Adjacent network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · Low
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub. Impact type from CWE-862.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00176 7th percentileScored 2026-11-07
Fix Fixed cilium (cilium): 1.17.17, 1.18.11, 1.19.5github.com/cilium/cilium (Go): 1.17.17, 1.19.5+1 more product

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
ciliumciliumbefore 1.17.17; 1.18.0 to before 1.18.11; 1.19.0 to before 1.19.51.17.17, 1.18.11, 1.19.5Patch availableCNA
—github.com/cilium/cilium (Go)before 1.17.171.17.17Patch availableGHSA-w7c2-w76w-5hmj
—github.com/cilium/ciliumCilium (Go)1.18.0 to before 1.18.111.18.11Patch availableGHSA-w7c2-w76w-5hmj
—github.com/cilium/cilium (Go)1.19.0 to before 1.19.51.19.5Patch availableGHSA-w7c2-w76w-5hmj
  • cilium Vendorcilium Affected before 1.17.17; 1.18.0 to before 1.18.11; 1.19.0 to before 1.19.5 Fixed in 1.17.17, 1.18.11, 1.19.5 Patch available CNA
  • github.com/cilium/cilium (Go) Vendor— Affected before 1.17.17 Fixed in 1.17.17 Patch available GHSA-w7c2-w76w-5hmj
  • github.com/cilium/ciliumCilium (Go) Vendor— Affected 1.18.0 to before 1.18.11 Fixed in 1.18.11 Patch available GHSA-w7c2-w76w-5hmj
  • github.com/cilium/cilium (Go) Vendor— Affected 1.19.0 to before 1.19.5 Fixed in 1.19.5 Patch available GHSA-w7c2-w76w-5hmj

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:cilium:cilium:*:*:*:*:*:*:*:*before 1.17.17; 1.18.0 to before 1.18.11; 1.19.0 to before 1.19.5Vulnerablecilium
  • cpe:2.3:a:cilium:cilium:*:*:*:*:*:*:*:* Versions before 1.17.17; 1.18.0 to before 1.18.11; 1.19.0 to before 1.19.5 Vulnerable ·cilium

Remediation

  • Fix · CNA cilium (cilium) Fixed in 1.17.17, 1.18.11, 1.19.5
  • Fix · GHSA-w7c2-w76w-5hmj github.com/cilium/cilium (Go) Fixed in 1.17.17 Advisory →
  • Fix · GHSA-w7c2-w76w-5hmj github.com/cilium/ciliumCilium (Go) Fixed in 1.18.11 Advisory →
  • Fix · GHSA-w7c2-w76w-5hmj github.com/cilium/cilium (Go) Fixed in 1.19.5 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-56742
  2. 2026-10-03 Alias added: GHSA-w7c2-w76w-5hmj

References

Patch 4

Advisory 2

Other 4

  • TI-2024-32092 CIDR deny policies may not take effect when a more narrow CIDR allow is present CVSS 3.1HIGH 8.7
  • TI-2023-12305 Cilium eBPF filters may be temporarily removed during agent restart CVSS 3.1CRITICAL 9.8
  • TI-2023-20486 Cilium NetworkPolicy bypass via pod labels CVSS 3.1CRITICAL 9.0
  • TI-2022-11721 Incorrect Default Permissions in Cilium CVSS 3.1HIGH 8.8
  • TI-2026-36600 Cilium: Sensitive information disclosure and cluster disruption via local Envoy admin socket access CVSS 3.1CRITICAL 9.2
  • TI-2022-11722 Improper Privilege Management in Cilium CVSS 3.1HIGH 8.2
See all 34 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences