Is CVE-2026-55636 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-55636 being exploited in the wild.

How severe is CVE-2026-55636?

Medium severity, with a CVSS score of 5.7, published 15 September 2026.

Which products and versions are affected?

github.com/projectcapsule/capsule (Go) >= 0.13.0, < 0.13.6, SEMVER:introduced=0.13.0,fixed=0.13.6.

Is there a fix for CVE-2026-55636?

Yes. github.com/projectcapsule/capsule (Go): upgrade to 0.13.6 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-55636 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-55636?

Check whether you run github.com/projectcapsule/capsule (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-55636: Clastix Capsule incorrect authorization via typo in namespaces/finalize webhook

Q: Is there a fix for CVE-2026-55636?

Yes. github.com/projectcapsule/capsule (Go): upgrade to 0.13.6 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-55636 attacked?

It is attacked over the network, in a software library.

Q: Am I affected by CVE-2026-55636?

Check whether you run github.com/projectcapsule/capsule (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-55636 · Severity: medium · CVSS 5.7 · Published 2026-09-15

Capsule, a multi-tenancy tool for Kubernetes, contains a configuration error that allows users with specific permissions to bypass security restrictions. Due to a typo in the software's validation rules, an attacker could modify protected labels on a namespace, potentially leading to a takeover of tenant resources. This bypasses intended isolation between different users or departments sharing the same cluster.

Technologies: github.com/projectcapsule/capsule (Go). Vendors: Go.

Quick answers

Is CVE-2026-55636 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-55636 being exploited in the wild.
How severe is CVE-2026-55636?: Medium severity, with a CVSS score of 5.7, published 15 September 2026.
Which products and versions are affected?: github.com/projectcapsule/capsule (Go) >= 0.13.0, < 0.13.6, SEMVER:introduced=0.13.0,fixed=0.13.6.
Is there a fix for CVE-2026-55636?: Yes. github.com/projectcapsule/capsule (Go): upgrade to 0.13.6 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-55636 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-55636?: Check whether you run github.com/projectcapsule/capsule (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

github.com/projectcapsule/capsule (Go): upgrade to 0.13.6 or later
```
go get github.com/projectcapsule/capsule@v0.13.6
```

Technical details

An incorrect authorization vulnerability exists in Capsule due to a singular/plural typo in the validating webhook configuration. Specifically, the rule uses 'namespace/finalize' instead of the required plural 'namespaces/finalize'. Because Kubernetes admission webhooks match against plural resource names, this typo causes the webhook to ignore requests to the finalize subresource. An attacker with 'namespaces/finalize' RBAC permissions can exploit this to modify namespace labels, such as 'capsule.clastix.io/tenant', bypassing the intended security logic. This issue is an incomplete fix for a previous vulnerability (CVE-2026-30963) and is resolved in version 0.13.6.

Affected products

Clastix Capsule >= 0.13.0, < 0.13.6

Identifiers

CVE-2026-55636
GHSA-gwxr-7h77-7777
GO-2026-5406

Timeline

2026-06-17: advisory: GHSA-gwxr-7h77-7777 published
2026-06-17: patched: Fixed in version 0.13.6

References

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