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Vulnerability · Published Sep 18, 2026 · Assigned by GitHub_M

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

High 7.1

In plain English

A high-severity incorrect authorization in capsule from projectcapsule. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 27% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.1High
Exploit odds (30 days)0.3%top 73.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Gogithub.com/projectcapsule/capsule0.13.7GHSA-gjw4-3v3v-rqxg
Gogithub.com/projectcapsule/capsule0.13.7GO-2026-6520

Affected products (as reported)

VendorProductVersions
projectcapsule capsule < 0.13.7

Weakness: CWE-697, CWE-863 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:H/A:N

References