Cyber Resilience

CVE-2026-40868

Kyverno ≤ 1.16.4

Public PoC
Published
21 April 2026
Modified
27 April 2026
Patch / advisory
View advisory
CVSS Score v3.1 8.1
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
EPSS Score 0.0029 21th percentile
Risk Priority 59 floored blend · peak EPSS

Summary

CVE-2026-40868 is a high-severity Insecure Storage of Sensitive Information (CWE-922) vulnerability in Kyverno Kyverno. Its CVSS base score is 8.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Unsecured Credentials (T1552); ranked at the 21th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and AC-6 (Least Privilege) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-40868 is a vulnerability in Kyverno, a policy engine for cloud native platform engineering teams. In versions prior to 1.16.4, the apiCall servicecall helper implicitly injects an Authorization: Bearer header using the Kyverno controller serviceaccount token when a policy does not explicitly set one. Since the context.apiCall.service.url is controlled by the policy, this allows the token to be sent to an attacker-controlled endpoint in a confused deputy scenario. The issue is scoped to ClusterPolicy and global context usage, as namespaced policies are blocked from servicecall by a gate in pkg/engine/apicall/apiCall.go.

An attacker with low privileges (PR:L) in a Kubernetes cluster can exploit this by creating or modifying a ClusterPolicy that invokes the servicecall helper with a malicious URL. This causes Kyverno to authenticate requests to the attacker's endpoint using its highly privileged serviceaccount token, enabling theft of the token for further privilege escalation, such as accessing cluster resources. The vulnerability has a CVSS score of 8.1 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N) and is associated with CWE-922 (Insecure Storage of Sensitive Information).

The Kyverno security advisory at GHSA-q93q-v844-jrqp states that the vulnerability is fixed in version 1.16.4. Security practitioners should upgrade to 1.16.4 or later to mitigate the issue.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

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.…

more

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.

CWE(s)
CWE-922

Related Threats

MITRE ATT&CK Enterprise Techniques

T1552 Unsecured Credentials Credential Access
Adversaries may search compromised systems to find and obtain insecurely stored credentials.
attack.mitre.org →
T1552.001 Credentials In Files Credential Access
Adversaries may search local file systems and remote file shares for files containing insecurely stored credentials.
attack.mitre.org →
T1552.004 Private Keys Credential Access
Adversaries may search for private key certificate files on compromised systems for insecurely stored credentials.
attack.mitre.org →
T1552.006 Group Policy Preferences Credential Access
Adversaries may attempt to find unsecured credentials in Group Policy Preferences (GPP).
attack.mitre.org →
T1552.002 Credentials in Registry Credential Access
Adversaries may search the Registry on compromised systems for insecurely stored credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-41323Same product: Kyverno Kyverno
CVE-2023-47630Same product: Kyverno Kyverno
CVE-2025-29778Same product: Kyverno Kyverno
CVE-2025-46342Same product: Kyverno Kyverno
CVE-2026-23881Same product: Kyverno Kyverno
CVE-2026-4789Same product: Kyverno Kyverno
CVE-2026-41485Same product: Kyverno Kyverno
CVE-2025-47281Same product: Kyverno Kyverno
CVE-2026-41068Same product: Kyverno Kyverno
CVE-2026-22039Same product: Kyverno Kyverno

Affected Assets

kyverno
kyverno
≤ 1.16.4

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 3 hardening rules · 2 OS baselines
Validate
Prove the fix (OWASP ASVS)

—

Mitigating Controls (NIST 800-53 r5) AI

AC-3 Access Enforcement good match

Enforces approved authorizations for logical access to stored information, directly stopping unauthorized read/write.

SC-28 Protection of Information at Rest good match

Requires protection of confidentiality/integrity for information at rest, directly addressing insecure storage.

AC-6 Least Privilege good match

Limits privileges so only authorized accesses to sensitive stored data are permitted.

AC-16 Security and Privacy Attributes partial match

Associates security attributes with information to support proper access decisions on storage.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-05 mostly match
prevents

Enforces least-privilege permissions and authorization reviews that limit read/write access to stored sensitive data.

PR.DS-01 mostly match
prevents

Directly protects data-at-rest confidentiality via encryption or access controls that prevent unauthorized reads.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.7.10 Storage media none match
mitigates

Secure reuse and disposal procedures, including cryptographic wiping and physical destruction, stop the insecure storage of sensitive data on media that may later be accessed by unauthorized actors.

A.7.14 Secure disposal or re-use of equipment none match
prevents

Mandating secure disposal techniques stops the insecure retention of sensitive information on storage media that leaves organizational control.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Windows Server 2016 (2 rules)
  • V-224973 The Active Directory Domain Controllers Organizational Unit (OU) object must have the proper access control permissions. prevents CWE-922
  • V-224974 Domain-created Active Directory Organizational Unit (OU) objects must have proper access control permissions. prevents CWE-922
Windows Server 2019 (1 rule)
  • V-205743 Windows Server 2019 organization created Active Directory Organizational Unit (OU) objects must have proper access control permissions. prevents CWE-922

References