GHSA-GJ49-89WH-H4GJ

Vulnerability from github – Published: 2026-04-25 23:39 – Updated: 2026-05-13 13:37
VLAI
Summary
Cillium exposes sensitive information included in the cilium-bugtool debug archive
Details

Impact

The output of cilium-bugtool can contain sensitive data when the tool is run against Cilium deployments with WireGuard encryption enabled.

Users of WireGuard Transparent Encryption are affected. The sensitive data is the WireGuard private key (cilium_wg0.key) used for node-to-node encrypted communication

cilium-bugtool is a debugging tool that is typically invoked manually and does not run during the normal operation of a Cilium cluster. It is also invoked when gathering sysdumps using the Cilium CLI's cilium sysdump command.

Patches

This issue affects:

  • Cilium v1.19 between v1.19.0 and v1.19.2 inclusive
  • Cilium v1.18 between v1.18.0 and v1.18.8 inclusive
  • All versions of Cilium prior to v1.17.15

This issue has been patched in:

  • Cilium v1.19.3
  • Cilium v1.18.9
  • Cilium v1.17.15

Workarounds

There is no workaround to this issue.

Users who have previously shared bugtool or sysdump archives from WireGuard-enabled nodes should rotate the WireGuard keys on the affected nodes. This can be done by deleting the key file and restarting the Cilium agent, which will generate a new key pair.

Acknowledgements

The Cilium community has worked together with members of Isovalent to prepare these mitigations. Cillium extends special thanks to @kodareef5 for reporting the issue and @tklauser for their work on triaging and remediating this issue.

For more information

If there are any questions or comments about this advisory, please reach out on Slack.

Cilium strongly encourages the reporting of suspected vulnerabilities to the security mailing list at security@cilium.io. This is a private mailing list for the Cilium security team, and the report will be treated as top priority.

Severity
7.9 (High)
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/cilium/cilium"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.17.15"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/cilium/cilium"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.18.0"
            },
            {
              "fixed": "1.18.9"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/cilium/cilium"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.19.0"
            },
            {
              "fixed": "1.19.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-41520"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-200",
      "CWE-312"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-25T23:39:37Z",
    "nvd_published_at": "2026-05-08T23:16:35Z",
    "severity": "HIGH"
  },
  "details": "### Impact\nThe output of `cilium-bugtool` can contain sensitive data when the tool is run against Cilium deployments with WireGuard encryption enabled.\n\nUsers of [WireGuard Transparent Encryption](https://docs.cilium.io/en/stable/security/network/encryption-wireguard/) are affected.\nThe sensitive data is  the WireGuard private key (`cilium_wg0.key`) used for node-to-node encrypted communication\n\n`cilium-bugtool` is a debugging tool that is typically invoked manually and does not run during the normal operation of a Cilium cluster. It is also invoked when gathering sysdumps using the Cilium CLI\u0027s `cilium sysdump` command.\n\n### Patches\nThis issue affects:\n\n- Cilium v1.19 between v1.19.0 and v1.19.2 inclusive\n- Cilium v1.18 between v1.18.0 and v1.18.8 inclusive\n- All versions of Cilium prior to v1.17.15\n\nThis issue has been patched in:\n\n- Cilium v1.19.3\n- Cilium v1.18.9\n- Cilium v1.17.15\n\n\n### Workarounds\nThere is no workaround to this issue.\n\nUsers who have previously shared bugtool or sysdump archives from WireGuard-enabled nodes should rotate the WireGuard keys on the affected nodes. This can be done by deleting the key file and restarting the Cilium agent, which will generate a new key pair.\n\n### Acknowledgements\n\nThe Cilium community has worked together with members of Isovalent to prepare these mitigations. Cillium extends special thanks to @kodareef5  for reporting the issue and  @tklauser for their work on triaging and remediating this issue.\n\n### For more information\n\nIf there are any questions or comments about this advisory, please reach out on [Slack](https://docs.cilium.io/en/latest/community/community/).\n\nCilium strongly encourages the reporting of suspected vulnerabilities to the security mailing list at [security@cilium.io](mailto:security@cilium.io). This is a private mailing list for the Cilium security team, and the report will be treated as top priority.",
  "id": "GHSA-gj49-89wh-h4gj",
  "modified": "2026-05-13T13:37:56Z",
  "published": "2026-04-25T23:39:37Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/cilium/cilium/security/advisories/GHSA-gj49-89wh-h4gj"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-41520"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/cilium/cilium"
    },
    {
      "type": "WEB",
      "url": "https://github.com/cilium/cilium/releases/tag/v1.17.15"
    },
    {
      "type": "WEB",
      "url": "https://github.com/cilium/cilium/releases/tag/v1.18.9"
    },
    {
      "type": "WEB",
      "url": "https://github.com/cilium/cilium/releases/tag/v1.19.3"
    },
    {
      "type": "WEB",
      "url": "http://docs.cilium.io/en/stable/security/network/encryption-wireguard"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Cillium exposes sensitive information included in the cilium-bugtool debug archive"
}


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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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