What’s Vulnerable › Vulnerabilities

CVE-2026-61794: Capsule: Malformed ForbiddenAnnotations.Regex can bypass Tenant validation and trigger namespace admission panic

• Severity: medium (CVSS 6.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-18 · updated 2026-09-24
• Weakness: CWE-20

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

• projectcapsule capsule: from 0.13.0, < 0.13.7

References

• https://github.com/projectcapsule/capsule/commit/8d89d6865df6f41c7faa22fc9e807a57b01bfd0e
• https://github.com/projectcapsule/capsule/pull/1983
• https://github.com/projectcapsule/capsule/releases/tag/v0.13.7
• https://github.com/projectcapsule/capsule/security/advisories/GHSA-gxjc-74v5-3vx3
• https://github.com/projectcapsule/capsule/security/advisories/GHSA-gxjc-74v5-3vx3

Get alerted when CVE-2026-61794 or the next vulnerability affects your stack