Is there a patch available for CVE-2026-41187?

Yes, a patch is available for CVE-2026-41187. Update the affected software to the latest version immediately.

Tigera Calico CVE-2026-41187

Q: What is the CVSS score of CVE-2026-41187?

CVE-2026-41187 has a CVSS 4.0 base score of 6.2 (Medium). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:L/SC:N/SI:L/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.3%.

EUVD-2026-51154 MEDIUM

Improper Authorization (CWE-285)

2026-07-30 Tigera

GHSA-38w4-qxg9-xg36

Authentication Bypass Calico Calico Enterprise Calico Cloud Tigera

6.2

CVSS 4.0 · Vendor: Tigera

Severity by source

Vendor (Tigera) PRIMARY

6.2 MEDIUM

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:L/SC:N/SI:L/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

vuln.today AI

7.6 HIGH

Kubernetes API is network-accessible (AV:N); PR:H because `deletecollection` grant is required; scope change (S:C) because policy deletion cascades to degrade enforcement for all cluster workloads; no confidentiality impact; high availability from bulk policy removal.

3.1 AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:L/A:H

4.0 AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:H

Primary rating from Vendor (Tigera).

CVSS VectorVendor: Tigera

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Lifecycle Timeline

Source Code Evidence Fetched

Jul 30, 2026 - 15:34 vuln.today

Analysis Generated

Jul 30, 2026 - 15:34 vuln.today

CVE Published

Jul 30, 2026 - 14:45 cve.org

MEDIUM 6.2

DescriptionCVE.org

Calico's apiserver wraps tier-scoped resources so that every operation runs through AuthorizeTierOperation, but the Delete override on NetworkPolicy, GlobalNetworkPolicy, and their staged variants is not invoked for DeleteCollection requests. A user holding the deletecollection verb or wildcard verbs on tier-scoped policy resources can bulk-delete policies in tiers they otherwise have no rights on, breaking the tier authorization boundary.

AnalysisAI

Tier authorization bypass in Tigera Calico's apiserver allows an authenticated high-privileged user to bulk-delete NetworkPolicy, GlobalNetworkPolicy, and their staged variants across restricted tiers without authorization. The DeleteCollection Kubernetes verb was not routed through AuthorizeTierOperation - the per-tier enforcement gate that governs all other write operations - meaning any principal holding deletecollection or wildcard verbs on tier-scoped policy resources could silently collapse network enforcement boundaries in tiers they have no legitimate access to. No public exploit or CISA KEV listing exists at time of analysis; four upstream patches have been merged and a vendor advisory (TTA-2026-006) has been published.

Technical ContextAI

Calico's apiserver enforces multi-tenancy through a tiered policy model: NetworkPolicy, GlobalNetworkPolicy, StagedNetworkPolicy, and StagedGlobalNetworkPolicy are scoped to named tiers with independent RBAC controls. The storage layer wraps Delete operations to invoke AuthorizeTierOperation, ensuring that a principal can only delete policies in tiers where they hold explicit permission. However, in Kubernetes, deletecollection is a distinct RBAC verb from delete and routes through a separate storage code path. The fix - visible in PR #12731 - adds VerbDeleteCollection as an explicit constant in calculator.go and extends the RBAC calculator to expand this verb across gettable tiers, mirroring how every other tier-aware verb is handled. Without this, wildcard grants (*) or explicit deletecollection grants were never intersected against per-tier authorization. CWE-285 (Improper Authorization) is the precise root cause: a specific verb was omitted from the enforcement path, creating an authorization decision gap. Affected products per CPE: cpe:2.3:a:tigera:calico:*, cpe:2.3:a:tigera:calico_enterprise:*, cpe:2.3:a:tigera:calico_cloud:*.

RemediationAI

Apply the patches referenced in Tigera security advisory TTA-2026-006 at https://www.tigera.io/security-bulletins/tta-2026-006/. Four upstream pull requests have been merged addressing this issue across product variants: https://github.com/projectcalico/calico/pull/12731, https://github.com/projectcalico/calico/pull/12735, https://github.com/projectcalico/calico/pull/12736, and https://github.com/projectcalico/calico/pull/12737. Exact patched release versions are not confirmed from available data - upstream PRs are merged but tagged release versions must be verified against the vendor advisory before deployment. As an immediate compensating control prior to patching, audit all ClusterRoles and Roles granting the deletecollection verb or wildcard verbs (*) on Calico tier-scoped resources (NetworkPolicy, GlobalNetworkPolicy, StagedNetworkPolicy, StagedGlobalNetworkPolicy) and remove or explicitly scope them; note that removing wildcard verb grants may affect legitimate Kubernetes administrative tooling such as kubectl delete --all workflows and should be tested before enforcement.