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Medium · 6.8 CVE-2026-61794 EUVD-2026-83055GHSA-gxjc-74v5-3vx3GO-2026-6521

Capsule: Malformed ForbiddenAnnotations.Regex can bypass Tenant validation and trigger namespace admission panic

Published Sep 18, 2026 · Updated Sep 22, 2026 · Assigned by GitHub_M

Description

Capsule is a multi-tenancy and policy-based framework for Kubernetes. From 0.13.0 until 0.13.7, the Tenant update validation in internal/webhook/tenant/validation/forbidden_annotations_regex.go compiles ForbiddenLabels.Regex for both the labels and annotations checks instead of validating ForbiddenAnnotations.Regex. An administrator who can update a Tenant can therefore persist a malformed ForbiddenAnnotations.Regex while leaving the labels expression valid. Namespace creation or update later passes the stored expression through pkg/api/forbidden_list.go, where regexp.MustCompile can panic during forbidden metadata validation and deny namespace operations for the affected tenant. This issue is fixed in version 0.13.7.

Affected products

VendorProductAffectedFixed
projectcapsule capsule >= 0.13.0, < 0.13.7 —

Affected packages

EcosystemPackageAffectedFixedRecord
Go github.com/projectcapsule/capsule >= 0.13.0, < 0.13.7 0.13.7 GHSA-gxjc-74v5-3vx3

References