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TI-2026-40916 Aliases CVE-2026-56743GHSA-fm8w-2m5w-9j7r

Incorrect authorization in cilium

Priority LOW 24CWE-863Published · Updated

Key facts

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

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-863.

Summary

Cilium is a networking, observability, and security solution. From 1.19.0 to 1.19.4, standard Kubernetes NetworkPolicy specifications using CIDR-based ipBlock rules without pod or namespace selectors erroneously generate a wildcard namespace allow rule when Cilium is configured with a custom clusterName rather than the default any value. The parser incorrectly instantiates a pod selector on selectorless peer definitions, allowing traffic from other workloads in the same namespace as the subject of the policy. This issue is fixed in version 1.19.5.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00248 16th percentileScored 2026-11-07
Fix Fixed cilium (cilium): 1.19.5github.com/cilium/cilium (Go): 1.19.5

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
ciliumcilium1.19.0 to before 1.19.51.19.5Patch availableCNA
—github.com/cilium/cilium (Go)1.19.0 to before 1.19.51.19.5Patch availableGHSA-fm8w-2m5w-9j7r
  • cilium Vendorcilium Affected 1.19.0 to before 1.19.5 Fixed in 1.19.5 Patch available CNA
  • github.com/cilium/cilium (Go) Vendor— Affected 1.19.0 to before 1.19.5 Fixed in 1.19.5 Patch available GHSA-fm8w-2m5w-9j7r

CPE configurations NVD · 1

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

Remediation

  • Fix · CNA cilium (cilium) Fixed in 1.19.5
  • Fix · GHSA-fm8w-2m5w-9j7r github.com/cilium/cilium (Go) Fixed in 1.19.5 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-56743
  2. 2026-10-03 Alias added: GHSA-fm8w-2m5w-9j7r

References

Patch 4

Advisory 2

Other 2

  • 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-2026-40915 Cilium: Namespaced HTTPRoutes can redirect traffic to other namespaces CVSS 3.1HIGH 8.9
See all 34 →

Sources

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