CVE-2026-56743

Network policy bypass via selectorless ipBlock parsing

Published Jul 15, 2026 · Updated Jul 15, 2026

Incorrect authorization in Cilium 1.19.0 through 1.19.4 allows remote authenticated users to bypass ingress policy via same-namespace traffic. The pkg/k8s NetworkPolicy parser instantiates a pod selector for an ipBlock-only peer and appends an unintended wildcard namespace selector. Exploitation requires a custom clusterName and a standard NetworkPolicy ipBlock peer without pod or namespace selectors, exposing protected pods to other workloads in their namespace.

CVSS severity5.4
Medium
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in Cilium 1.19.0 through 1.19.4 allows remote authenticated users to bypass ingress policy via same-namespace traffic. The pkg/k8s NetworkPolicy parser instantiates a pod selector for an ipBlock-only peer and appends an unintended wildcard namespace selector. Exploitation requires a custom clusterName and a standard NetworkPolicy ipBlock peer without pod or namespace selectors, exposing protected pods to other workloads in their namespace.

The record

CVE
CVE-2026-56743
Published
Jul 15, 2026
Updated
Jul 15, 2026
Vendor
Cilium
Product
Cilium
Classifications
CWE-863, T1210
Attack vector
adjacent
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 1.19.0, < 1.19.5

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesauthenticated

What is affected?

Cilium · Ciliumversion=>= 1.19.0, < 1.19.5

Published CVSS scores

5.4GitHub, Inc.CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-863Incorrect Authorization
T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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