CVE-2026-41520: Github.com/cilium/cilium Cillium Exposes Sensitive Information Included Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-gj49-89wh-h4gj",
  "modified" : "2026-05-13T13:37:56Z",
  "published" : "2026-04-25T23:39:37Z",
  "aliases" : [ "CVE-2026-41520" ],
  "summary" : "Cillium exposes sensitive information included in the cilium-bugtool debug archive",
  "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's `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.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/cilium/cilium"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.17.15"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/cilium/cilium"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.18.0"
      }, {
        "fixed" : "1.18.9"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/cilium/cilium"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.19.0"
      }, {
        "fixed" : "1.19.3"
      } ]
    } ]
  } ],
  "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"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-200", "CWE-312" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-25T23:39:37Z",
    "nvd_published_at" : "2026-05-08T23:16:35Z"
  }
}