Vulnerability-Lookup

CVE-2026-26963 (GCVE-0-2026-26963)

Vulnerability from cvelistv5 – Published: 2026-02-19 23:38 – Updated: 2026-02-20 15:36

Title

Cilium may not enforce host firewall policies when Native Routing, WireGuard and Node Encryption are enabled

Summary

Cilium is a networking, observability, and security solution with an eBPF-based dataplane. Versions 1.18.0 through 1.18.5 will incorrectly permit traffic from Pods on other nodes when Native Routing, WireGuard and Node Encryption are enabled. This issue has been fixed in version 1.18.6.

Severity

6.1 (Medium)


                        
                          CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-863 - Incorrect Authorization

Assigner

GitHub_M

References

4 references

URL	Tags
https://github.com/cilium/cilium/security/advisor…	x_refsource_CONFIRM
https://github.com/cilium/cilium/pull/42892	x_refsource_MISC
https://github.com/cilium/cilium/commit/88e28e1e6…	x_refsource_MISC
https://github.com/cilium/cilium/releases/tag/v1.18.6	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
cilium	cilium	Affected: >= 1.18.0, < 1.18.6

Show details on NVD website

JSON

To clipboard

{
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      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-26963",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-02-20T15:26:45.815584Z",
                "version": "2.0.3"
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            }
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          "shortName": "CISA-ADP"
        },
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      }
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    "cna": {
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          "vendor": "cilium",
          "versions": [
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        }
      ],
      "metrics": [
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          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "ADJACENT_NETWORK",
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            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
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            "privilegesRequired": "NONE",
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            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N",
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          }
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            }
          ]
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      ],
      "providerMetadata": {
        "dateUpdated": "2026-02-19T23:38:36.110Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
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        },
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          "name": "https://github.com/cilium/cilium/pull/42892",
          "tags": [
            "x_refsource_MISC"
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          "url": "https://github.com/cilium/cilium/pull/42892"
        },
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          "name": "https://github.com/cilium/cilium/commit/88e28e1e62c0b1a02c3f0fc22d888ac9eefbe885",
          "tags": [
            "x_refsource_MISC"
          ],
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        },
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          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/cilium/cilium/releases/tag/v1.18.6"
        }
      ],
      "source": {
        "advisory": "GHSA-5r23-prx4-mqg3",
        "discovery": "UNKNOWN"
      },
      "title": "Cilium may not enforce host firewall policies when Native Routing, WireGuard and Node Encryption are enabled"
    }
  },
  "cveMetadata": {
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    "datePublished": "2026-02-19T23:38:36.110Z",
    "dateReserved": "2026-02-16T22:20:28.612Z",
    "dateUpdated": "2026-02-20T15:36:37.658Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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    "vulnrichment": {
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}

bit-cilium-2026-26963

Vulnerability from bitnami_vulndb

Published

2026-02-21 08:36

Modified

2026-02-21 09:08

Summary

Cilium may not enforce host firewall policies when Native Routing, WireGuard and Node Encryption are enabled

Details

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "cilium",
        "purl": "pkg:bitnami/cilium"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.18.0"
            },
            {
              "fixed": "1.18.6"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "severity": [
        {
          "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
          "type": "CVSS_V3"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-26963"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:cilium:cilium:*:*:*:*:*:*:*:*"
    ],
    "severity": "Medium"
  },
  "details": "Cilium is a networking, observability, and security solution with an eBPF-based dataplane. Versions 1.18.0 through 1.18.5 will incorrectly permit traffic from Pods on other nodes when Native Routing, WireGuard and Node Encryption are enabled. This issue has been fixed in version 1.18.6.",
  "id": "BIT-cilium-2026-26963",
  "modified": "2026-02-21T09:08:21.332Z",
  "published": "2026-02-21T08:36:53.368Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/cilium/cilium/commit/88e28e1e62c0b1a02c3f0fc22d888ac9eefbe885"
    },
    {
      "type": "WEB",
      "url": "https://github.com/cilium/cilium/pull/42892"
    },
    {
      "type": "WEB",
      "url": "https://github.com/cilium/cilium/releases/tag/v1.18.6"
    },
    {
      "type": "WEB",
      "url": "https://github.com/cilium/cilium/security/advisories/GHSA-5r23-prx4-mqg3"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-26963"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "Cilium may not enforce host firewall policies when Native Routing, WireGuard and Node Encryption are enabled"
}

FKIE_CVE-2026-26963

Vulnerability from fkie_nvd - Published: 2026-02-20 00:16 - Updated: 2026-06-17 10:26

Severity

6.1 (Medium) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
5.4 (Medium) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Summary

References

URL	Tags
security-advisories@github.com	https://github.com/cilium/cilium/commit/88e28e1e62c0b1a02c3f0fc22d888ac9eefbe885	Patch
security-advisories@github.com	https://github.com/cilium/cilium/pull/42892	Issue Tracking
security-advisories@github.com	https://github.com/cilium/cilium/releases/tag/v1.18.6	Release Notes
security-advisories@github.com	https://github.com/cilium/cilium/security/advisories/GHSA-5r23-prx4-mqg3	Patch, Vendor Advisory

Impacted products

	Vendor	Product	Version
	cilium	cilium	*

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "cilium",
          "vendor": "cilium",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 1.18.0, \u003c 1.18.6"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:cilium:cilium:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "1EB1228F-3E28-4790-A9E0-D6DE184F39D5",
              "versionEndExcluding": "1.18.6",
              "versionStartIncluding": "1.18.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Cilium is a networking, observability, and security solution with an eBPF-based dataplane. Versions 1.18.0 through 1.18.5 will incorrectly permit traffic from Pods on other nodes when Native Routing, WireGuard and Node Encryption are enabled. This issue has been fixed in version 1.18.6."
    },
    {
      "lang": "es",
      "value": "Cilium es una soluci\u00f3n de red, observabilidad y seguridad con un plano de datos basado en eBPF. Las versiones 1.18.0 a la 1.18.5 permitir\u00e1n incorrectamente el tr\u00e1fico desde Pods en otros nodos cuando el Enrutamiento Nativo, WireGuard y el Cifrado de Nodos est\u00e9n habilitados. Este problema ha sido solucionado en la versi\u00f3n 1.18.6."
    }
  ],
  "id": "CVE-2026-26963",
  "lastModified": "2026-06-17T10:26:27.533",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "ADJACENT_NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.1,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 2.7,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      },
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "ADJACENT_NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 5.4,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 2.5,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-26963",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-02-20T15:26:45.815584Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-02-20T00:16:16.167",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/cilium/cilium/commit/88e28e1e62c0b1a02c3f0fc22d888ac9eefbe885"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Issue Tracking"
      ],
      "url": "https://github.com/cilium/cilium/pull/42892"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Release Notes"
      ],
      "url": "https://github.com/cilium/cilium/releases/tag/v1.18.6"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ],
      "url": "https://github.com/cilium/cilium/security/advisories/GHSA-5r23-prx4-mqg3"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-863"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

GHSA-5R23-PRX4-MQG3

Vulnerability from github – Published: 2026-02-19 19:39 – Updated: 2026-02-20 16:46

Summary

Cilium may not enforce host firewall policies when Native Routing, WireGuard and Node Encryption are enabled

Details

Impact

Host Policies will incorrectly permit traffic from Pods on other nodes when all of the following configurations are enabled: * Native Routing * WireGuard * Node Encryption (beta)

These options are disabled by default in Cilium.

Patches

This issue was fixed by #42892.

This issue affects:

Cilium v1.18 between v1.18.0 and v1.18.5 inclusive

This issue is fixed in:

Cilium v1.18.6

Workarounds

There is currently no officially verified or comprehensive workaround for this issue. The following procedure has been validated strictly within a local 'Kind' environment and has not undergone exhaustive testing across diverse production architectures. Proceed with caution.

To mitigate the identified traffic bypass, ensure all ingress traffic from the cilium_wg0 interface is explicitly routed to cilium_host for policy enforcement. This ensures that host-level security policies are applied to decrypted WireGuard traffic. Execute the following configuration on each CiliumNode:

# IPv4 Traffic
ip rule add iif cilium_wg0 table 300
ip route add default dev cilium_host table 300

# IPv6 Traffic
ip -6 rule add iif cilium_wg0 table 300
ip -6 route add default dev cilium_net table 300

Acknowledgements

Special thanks to @julianwiedmann for reporting the issue and helping with the resolution.

For more information

If you think you have found a vulnerability affecting Cilium, we strongly encourage you to report it to our security mailing list at security@cilium.io. This is a private mailing list for the Cilium security team, and your report will be treated as top priority. Please also address any comments or questions on this advisory to the same mailing list.

Severity

6.1 (Medium)


                  
                    CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c 1.18.5"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/cilium/cilium"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.18.0"
            },
            {
              "fixed": "1.18.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-26963"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-863"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-02-19T19:39:01Z",
    "nvd_published_at": "2026-02-20T00:16:16Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n\n[Host Policies](https://docs.cilium.io/en/stable/security/policy/language/#host-policies) will incorrectly permit traffic from Pods on other nodes when all of the following configurations are enabled:\n* [Native Routing](https://docs.cilium.io/en/stable/network/concepts/routing/#native-routing)\n* [WireGuard](https://docs.cilium.io/en/stable/security/policy/language/#host-policies)\n* [Node Encryption](https://docs.cilium.io/en/stable/security/network/encryption-wireguard/#node-to-node-encryption-beta) (beta)\n\nThese options are disabled by default in Cilium.\n\n### Patches\n\nThis issue was fixed by #42892.\n\nThis issue affects:\n\n* Cilium v1.18 between v1.18.0 and v1.18.5 inclusive\n\nThis issue is fixed in:\n\n* Cilium v1.18.6\n\n### Workarounds\n\nThere is currently no officially verified or comprehensive workaround for this issue. The following procedure has been validated strictly within a local \u0027Kind\u0027 environment and has not undergone exhaustive testing across diverse production architectures. Proceed with caution.\n\nTo mitigate the identified traffic bypass, ensure all ingress traffic from the `cilium_wg0` interface is explicitly routed to `cilium_host` for policy enforcement. This ensures that host-level security policies are applied to decrypted WireGuard traffic. Execute the following configuration on each CiliumNode:\n\n```bash\n# IPv4 Traffic\nip rule add iif cilium_wg0 table 300\nip route add default dev cilium_host table 300\n\n# IPv6 Traffic\nip -6 rule add iif cilium_wg0 table 300\nip -6 route add default dev cilium_net table 300\n```\n\n### Acknowledgements\n\nSpecial thanks to @julianwiedmann for reporting the issue and helping with the resolution.\n\n### For more information\n\nIf you think you have found a vulnerability affecting Cilium, we strongly encourage you to report it to our security mailing list at security@cilium.io. This is a private mailing list for the Cilium security team, and your report will be treated as top priority. Please also address any comments or questions on this advisory to the same mailing list.",
  "id": "GHSA-5r23-prx4-mqg3",
  "modified": "2026-02-20T16:46:49Z",
  "published": "2026-02-19T19:39:01Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/cilium/cilium/security/advisories/GHSA-5r23-prx4-mqg3"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-26963"
    },
    {
      "type": "WEB",
      "url": "https://github.com/cilium/cilium/pull/42892"
    },
    {
      "type": "WEB",
      "url": "https://github.com/cilium/cilium/commit/88e28e1e62c0b1a02c3f0fc22d888ac9eefbe885"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/cilium/cilium"
    },
    {
      "type": "WEB",
      "url": "https://github.com/cilium/cilium/releases/tag/v1.18.6"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Cilium may not enforce host firewall policies when Native Routing, WireGuard and Node Encryption are enabled"
}

Sightings

Author	Source	Type	Date	Other

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.

Detection rules are retrieved from Rulezet.

Action not permitted

CVE-2026-26963 (GCVE-0-2026-26963)

bit-cilium-2026-26963

Vulnerability from bitnami_vulndb

FKIE_CVE-2026-26963

GHSA-5R23-PRX4-MQG3

Impact

Patches

Workarounds

Acknowledgements

For more information

Tags

Sightings

Nomenclature