Cyber Resilience

CVE-2026-41520

HighUpdated

Published: 08 May 2026

Published
08 May 2026
Modified
18 May 2026
KEV Added
Patch
CVSS Score v3.1 7.9 CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N
EPSS Score 0.0001 0.3th percentile
Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-41520 is a high-severity Exposure of Sensitive Information to an Unauthorized Actor (CWE-200) vulnerability in Cilium Cilium. Its CVSS base score is 7.9 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Private Keys (T1552.004); ranked at the 0.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

Cilium is a networking, observability, and security solution with an eBPF-based dataplane. Prior to versions 1.17.15, 1.18.9, and 1.19.3, the output of cilium-bugtool can contain sensitive data when the tool is run against Cilium deployments with WireGuard encryption enabled. This…

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issue has been patched in versions 1.17.15, 1.18.9, and 1.19.3.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1552.004 Private Keys Credential Access
Adversaries may search for private key certificate files on compromised systems for insecurely stored credentials.
Why these techniques?

Bugtool output leaks sensitive WireGuard private keys (CWE-312 cleartext exposure) enabling direct credential access.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v18.1

CVEs Like This One

CVE-2026-40965Shared CWE-200
CVE-2025-27685Shared CWE-312
CVE-2026-42151Shared CWE-200, CWE-312
CVE-2025-22612Shared CWE-200
CVE-2026-22240Shared CWE-200, CWE-312
CVE-2025-34206Shared CWE-312
CVE-2024-13796Shared CWE-200
CVE-2025-27784Shared CWE-200
CVE-2025-26001Shared CWE-200
CVE-2026-42826Shared CWE-200

Affected Assets

cilium
cilium
≤ 1.17.15 · 1.18.0 — 1.18.9 · 1.19.0 — 1.19.3

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-200 CWE-312

A data action map identifies locations where sensitive information may be exposed to unauthorized actors during processing or transfer.

addresses: CWE-200 CWE-312

The media protection policy defines requirements and procedures to prevent unauthorized disclosure or access to sensitive information on media.

addresses: CWE-200 CWE-312

Encrypting or otherwise protecting data at rest directly prevents unauthorized actors from reading sensitive information stored on disk or other media.

addresses: CWE-200 CWE-312

Directly prevents exposure of critical organizational information by applying OPSEC processes across the SDLC.

addresses: CWE-200

Automated marking applies security attributes to system outputs, making it harder for attackers to exploit unmarked sensitive information leading to unauthorized exposure.

addresses: CWE-200

Proper attribute retention and permitted-value enforcement limits unauthorized actors from accessing sensitive information lacking correct labels.

addresses: CWE-200

Prevents unauthorized exposure of sensitive information by prohibiting untrusted external systems from processing or storing it.

addresses: CWE-200

By enforcing authorization matching prior to sharing, the control reduces the risk of exposing sensitive information to unauthorized actors.

References