# CVE-2026-41520: Cilium sensitive information disclosure in cilium-bugtool

Source: https://junglewise.ai/threats/cve-2026-41520-cilium-sensitive-information-disclosure-in-cilium-bugtool  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-08. Updated: 2026-05-18  
License: CC BY 4.0 with a link back

CVE-2026-41520 · Severity: high · CVSS 7.9 · Published 2026-05-08

Cilium is a networking and security tool used to manage and secure communication between applications in cloud environments. A vulnerability in its diagnostic tool, cilium-bugtool, could allow sensitive information to be exposed in plain text when WireGuard encryption is enabled. If an attacker with high-level system access obtains these diagnostic logs, they could potentially access sensitive configuration data or encryption details, compromising the security of the network.

Technologies: [Cilium](https://junglewise.ai/threats/technologies/cilium), [github.com/cilium/cilium (Go)](https://junglewise.ai/threats/technologies/github-com-cilium-cilium). Vendors: [Cilium](https://junglewise.ai/threats/vendors/cilium), [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-41520 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-41520 being exploited in the wild.

**How severe is CVE-2026-41520?** High severity, with a CVSS score of 7.9, published 8 May 2026.

**Which products and versions are affected?** Cilium < 1.17.15, < 1.18.9, < 1.19.3; github.com/cilium/cilium (Go) SEMVER:introduced=0,fixed=1.17.15, SEMVER:introduced=0,fixed=1.17.15,introduced=1.18.0,fixed=1.18.9,introduced=1.19.0,fixed=1.19.3.

**Is there a fix for CVE-2026-41520?** Yes. github.com/cilium/cilium (Go): upgrade to 1.17.15, 1.19.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-41520 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-41520?** Check whether you run Cilium or github.com/cilium/cilium (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/cilium/cilium (Go): upgrade to 1.17.15, 1.19.3 or later

  ```sh
  go get github.com/cilium/cilium@v1.19.3
  ```


## Technical details

A sensitive information disclosure vulnerability exists in Cilium's diagnostic utility, cilium-bugtool. When the tool is executed on a Cilium deployment where WireGuard encryption is enabled, the resulting output may contain sensitive data in cleartext. This issue is classified under CWE-200 (Exposure of Sensitive Information) and CWE-312 (Cleartext Storage of Sensitive Information). An attacker with local access and high privileges (PR:H) could exploit this to retrieve sensitive cryptographic or configuration details from the bugtool's output. The vulnerability has been addressed in versions 1.17.15, 1.18.9, and 1.19.3 by ensuring sensitive data is properly redacted or excluded from diagnostic reports.

## Affected products

- Cilium Cilium < 1.17.15, < 1.18.9, < 1.19.3

## Identifiers

- CVE-2026-41520
- GHSA-gj49-89wh-h4gj
- GO-2026-5400

## Timeline

- 2026-04-15: patched: Fixes included in releases 1.17.15, 1.18.9, and 1.19.3
- 2026-05-08: disclosed: CVE published

## References

- [https://github.com/cilium/cilium/releases/tag/v1.17.15](https://github.com/cilium/cilium/releases/tag/v1.17.15)
- [https://github.com/cilium/cilium/releases/tag/v1.18.9](https://github.com/cilium/cilium/releases/tag/v1.18.9)
- [https://github.com/cilium/cilium/releases/tag/v1.19.3](https://github.com/cilium/cilium/releases/tag/v1.19.3)
- [https://github.com/cilium/cilium/security/advisories/GHSA-gj49-89wh-h4gj](https://github.com/cilium/cilium/security/advisories/GHSA-gj49-89wh-h4gj)

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