CVE-2026-53935

Cross-namespace traffic hijacking via service-map overwrite

Published Jul 7, 2026 · Updated Jul 7, 2026

Improper service-map handling in Cilium allows remote authenticated users to hijack cross-namespace Kubernetes Service traffic. The addressMatcher path installs a LocalRedirect pseudo-service over an existing ClusterIP frontend without checking ownership, replacing its service-map entry. Creation rights for CiliumLocalRedirectPolicy are required; deleting the policy leaves the original entry unrestored and stops translation for that Service.

CVSS severity6.9
Medium
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper service-map handling in Cilium allows remote authenticated users to hijack cross-namespace Kubernetes Service traffic. The addressMatcher path installs a LocalRedirect pseudo-service over an existing ClusterIP frontend without checking ownership, replacing its service-map entry. Creation rights for CiliumLocalRedirectPolicy are required; deleting the policy leaves the original entry unrestored and stops translation for that Service.

The record

CVE
CVE-2026-53935
Published
Jul 7, 2026
Updated
Jul 7, 2026
Vendor
Cilium
Product
Cilium
Classifications
CWE-863, T1557, T1498
Attack vector
adjacent
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 7, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 7, 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=< 1.17.16
  2. Affected versionversion=>= 1.18.2, < 1.18.10
  3. Affected versionversion=>= 1.19.0, < 1.19.4

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesauthenticated

What is affected?

Cilium · Ciliumversion=< 1.17.16; version=>= 1.18.2, < 1.18.10; version=>= 1.19.0, < 1.19.4

Published CVSS scores

6.9GitHub, Inc.CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:N/A:H

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
T1557Adversary-in-the-Middle
T1498Network Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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