CVE-2026-22039: Kyverno Cross-Namespace Privilege Escalation via Policy apiCall

Should you act?

Critical, preconditions apply

Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 0.6%, percentile 47: FIRST’s model estimates a 0.6% chance of exploitation activity in the next 30 days, higher than 47% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Needs an account (low (any account)). Exposure depends on who can log in.
• Only applies if your dependency tree includes github.com/kyverno/kyverno (Go) < 1.15.3, fixed in 1.15.3; github.com/kyverno/kyverno (Go) >= 1.16.0-rc.1, < 1.16.3, fixed in 1.16.3. Check your lockfile, including transitive dependencies.

What it is

Kyverno is a policy engine designed for cloud native platform engineering teams. Versions prior to 1.16.3 and 1.15.3 have a critical authorization boundary bypass in namespaced Kyverno Policy apiCall. The resolved urlPath is executed using the Kyverno admission controller ServiceAccount, with no enforcement that the request is limited to the policy’s namespace. As a result, any authenticated user with permission to create a namespaced Policy can cause Kyverno to perform Kubernetes API requests using Kyverno’s admission controller identity, targeting any API path allowed by that ServiceAccount’s RBAC. This breaks namespace isolation by enabling cross-namespace reads (for example, ConfigMaps and, where permitted, Secrets) and allows cluster-scoped or cross-namespace writes (for example, creating ClusterPolicies) by controlling the urlPath through context variable substitution. Versions 1.16.3 and 1.15.3 contain a patch for the vulnerability.

From the GitHub advisory

Summary

A critical authorization boundary bypass in namespaced Kyverno Policy apiCall. The resolved urlPath is executed using the Kyverno admission controller ServiceAccount, with no enforcement that the request is limited to the policy’s namespace.

As a result, any authenticated user with permission to create a namespaced Policy can cause Kyverno to perform Kubernetes API requests using Kyverno’s admission controller identity, targeting any API path allowed by that ServiceAccount’s RBAC. This breaks namespace isolation by enabling cross-namespace reads (for example, ConfigMaps and, where permitted, Secrets) and allows cluster-scoped or cross-namespace writes (for example, creating ClusterPolicies) by controlling the urlPath through context variable substitution.

Details

The vulnerability exists in how Kyverno handles apiCall context entries. The code substitutes variables into the URLPath field without sanitizing the output or validating that the resulting path is authorized for the scope of the policy.

Weakness type: CWE-269, CWE-918.

Product: github.com/kyverno/kyverno (Go) · Assigned by: GitHub_M · Published: 2026-01-27

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: low (any account)
• User interaction: none
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.59% probability of exploitation activity in the next 30 days; percentile 47.

Timeline

• 2026-01-27 — CVE record last updated
• 2026-01-27 — CVE record published by GitHub_M
• 2026-01-27 — GitHub-reviewed advisory GHSA-8p9x-46gm-qfx2 published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-8p9x-46gm-qfx2 github.com
2. CVE.org record CVE-2026-22039 cve.org
3. NVD entry CVE-2026-22039 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com

Critical Go advisories · Today’s Security Digest