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VulnerabilityPublished

CVE-2026-30963: projectcapsule capsule · Improper Input Validation

Affects projectcapsule capsuleSource CVE Database V5

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Not known to be exploited · CVSS 3.9 Low : upgrade to 0.13.0 when convenient.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score
3.9Low
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 12% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 0.13.0
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:L

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 1 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Upgrade capsule and projectcapsule/capsule to 0.13.0.

Affected software

ProductAffectedFixed in
projectcapsulecapsuleAffected
  • <0.13.0
Fixed in
  • 0.13.0
GitHubprojectcapsule/capsulepkg:github/projectcapsule/capsuleOther threatsAffected
  • <0.13.0
Fixed in
  • 0.13.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade Capsule to version 0.13.0 or later, which includes the fix by adding interception rules for the namespace/finalize and namespace/status subresources in the webhook configuration. Alternatively, manually add these subresources (namespaces and namespaces/status with namespace/finalize) to the ValidatingWebhookConfiguration rules to ensure they are validated.

Description

Capsule is a multi-tenancy and policy-based framework for Kubernetes. To defend against namespace hijacking achieved through update/patch operations on namespaces, Capsule uses a webhook to validate update requests targeting namespaces. However, in Kubernetes, the namespace/finalize and namespace/status subresource APIs can also modify various fields of a namespace, including the metadata field. Prior to version 0.13.0, the webhook does not define interception rules for these subresources. As a result, if a tenant administrator has permission to modify namespace/status or namespace/finalize, they can successfully perform namespace hijacking. Version 0.13.0 fixes the issue. Another mitigation is to add two subresources (namespaces and snamespaces/status with namespace/finalize within it) to the resources list in the ValidatingWebhookConfiguration rules.

References

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