CVE-2026-55636Public exploitNetwork attack vector

Tenant-label hijack via unmatched finalize webhook rule

Published Sep 15, 2026 · Updated Sep 15, 2026

Incorrect authorization in Project Capsule's Capsule 0.13.0 through 0.13.5 allows remote authenticated users to hijack namespace tenant labels. The Helm template names the validating-webhook resource namespace/finalize, so it never matches PUT requests for the plural namespaces/finalize resource. A user granted update permission on namespaces/finalize can bypass admission validation and reassign a namespace's tenant association.

CVSS severity5.7
Medium
EPSS probability0.28%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in Project Capsule's Capsule 0.13.0 through 0.13.5 allows remote authenticated users to hijack namespace tenant labels. The Helm template names the validating-webhook resource namespace/finalize, so it never matches PUT requests for the plural namespaces/finalize resource. A user granted update permission on namespaces/finalize can bypass admission validation and reassign a namespace's tenant association.

The record

CVE
CVE-2026-55636
Published
Sep 15, 2026
Updated
Sep 15, 2026
Vendor
Project Capsule
Product
Capsule
Classifications
CWE-863
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 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=>= 0.13.0, < 0.13.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Project Capsule · Capsuleversion=>= 0.13.0, < 0.13.6

Published CVSS scores

5.7GitHubCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:H/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-863Incorrect Authorization

Public exploit references

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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