{"id":"EUVD-2026-16771","revision":null,"records":[{"revision":"9410f4cc5a144b45bfececb2c17a0672","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-32241","aliases":[],"title":"Flannel vulnerable to cross-node remote code execution via extension backend BackendData injection","description":"Flannel is a network fabric for containers, designed for Kubernetes. The Flannel project includes an experimental Extension backend that allows users to easily prototype new backend types. In versions of Flannel prior to 0.28.2, this Extension backend is vulnerable to a command injection  that allows an attacker who can set Kubernetes Node annotations to achieve root-level arbitrary command execution on every flannel node in the cluster. The Extension backend's SubnetAddCommand and SubnetRemoveCommand receive attacker-controlled data via stdin (from the `flannel.alpha.coreos.com/backend-data` Node annotation). The content of this annotation is unmarshalled and piped directly to a shell command without checks. Kubernetes clusters using Flannel with the Extension backend are affected by this vulnerability. Other backends such as vxlan and wireguard are unaffected. The vulnerability is fixed in version v0.28.2. As a workaround, use Flannel with another backend such as vxlan or wireguard.","state":0,"publishedAt":"2026-03-27T19:31:48.276+00:00","modifiedAt":"2026-03-31T18:54:30.192+00:00","affected":[{"ecosystem":"Vendor product","name":"flannel","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"flannel-io\",\n                    \"product\": \"flannel\",\n                    \"versions\": [\n                        {\n                            \"version\": \"< 0.28.2\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.5,"severity":"HIGH"}],"references":["https://github.com/flannel-io/flannel/security/advisories/GHSA-vchx-5pr6-ffx2","https://github.com/flannel-io/flannel/releases/tag/v0.28.2"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-32241","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-32241","identifiers":["CVE-2026-32241"]},"retained":false,"historicalAffected":[]},{"revision":"77a2a035397e47cead4e67c075c02aac","observedAt":"2026-11-15T09:35:02.745+00:00","statement":{"source":"euvd","id":"EUVD-2026-16771","aliases":["CVE-2026-32241"],"title":"Flannel is a network fabric for containers, designed for Kubernetes. 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Kubernetes clusters using Flannel with the Extension backend are affected by this vulnerability. Other backends such as vxlan and wireguard are unaffected. The vulnerability is fixed in version v0.28.2. 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In versions of Flannel prior to 0.28.2, this Extension backend is vulnerable to a command injection  that allows an attacker who can set Kubernetes Node annotations to achieve root-level arbitrary command execution on every flannel node in the cluster. The Extension backend's SubnetAddCommand and SubnetRemoveCommand receive attacker-controlled data via stdin (from the `flannel.alpha.coreos.com/backend-data` Node annotation). The content of this annotation is unmarshalled and piped directly to a shell command without checks. Kubernetes clusters using Flannel with the Extension backend are affected by this vulnerability. Other backends such as vxlan and wireguard are unaffected. The vulnerability is fixed in version v0.28.2. 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Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-32241","identifiers":["CVE-2026-32241"]},"retained":false,"historicalAffected":[]},{"revision":"3532aa5fc71b420db7c809f20b7b483e","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GHSA-vchx-5pr6-ffx2","aliases":["CVE-2026-32241","GO-2026-4894"],"title":"Flannel has cross-node remote code execution via extension backend BackendData injection","description":"### Background\nThe Flannel project includes an experimental Extension backend that allows users to easily prototype new backend types. This backend uses shell commands stored in Kubernetes annotations to configure network connectivity on the node.\n\nNote: consumers are only affected by this vulnerability if they use the experimental Extension backend. Other backends such as vxlan and wireguard are unaffected.\n\n### Vulnerability\nThis Extension backend is vulnerable to a command injection that allows an attacker who can set Kubernetes Node annotations to achieve root-level arbitrary command execution on every flannel node in the cluster.\n\nThe Extension backend's SubnetAddCommand and SubnetRemoveCommand receive attacker-controlled data via stdin (from the `flannel.alpha.coreos.com/backend-data` Node annotation). The content of this annotation is unmarshalled and piped directly to a shell command without checks.\n\n### Impact\nKubernetes clusters using Flannel with the Extension backend are affected by this vulnerability. Other backends such as vxlan and wireguard are unaffected.\n\n### Patches\nThis is fixed in version v0.28.2.\n\n### Workaround \nIf consumers cannot update to a patched version, then use Flannel with another backend such as vxlan or wireguard.\n\n### Credits\nFlannel would like to thank  Shachar Tal from Palo Alto Networks for reporting this vulnerability.","state":0,"publishedAt":"2026-03-27T20:28:13+00:00","modifiedAt":"2026-09-10T03:50:41.2757579+00:00","affected":[{"ecosystem":"Go","name":"github.com/flannel-io/flannel","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"0.28.2"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"HIGH"}],"references":["https://github.com/flannel-io/flannel/security/advisories/GHSA-vchx-5pr6-ffx2","https://nvd.nist.gov/vuln/detail/CVE-2026-32241","https://github.com/flannel-io/flannel/commit/08bc9a4c990ae785d2fcb448f4991b58485cd26a","https://github.com/flannel-io/flannel","https://github.com/flannel-io/flannel/releases/tag/v0.28.2"],"sourceUrl":"https://github.com/advisories/GHSA-vchx-5pr6-ffx2","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-vchx-5pr6-ffx2","identifiers":["GHSA-vchx-5pr6-ffx2","CVE-2026-32241","GO-2026-4894"]},"retained":false,"historicalAffected":[]},{"revision":"d342d72e7fca4b9bb3db89687a3819b9","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GO-2026-4894","aliases":["CVE-2026-32241","GHSA-vchx-5pr6-ffx2"],"title":"Flannel has cross-node remote code execution via extension backend BackendData injection in github.com/flannel-io/flannel","description":"Flannel has cross-node remote code execution via extension backend BackendData injection in github.com/flannel-io/flannel","state":0,"publishedAt":"2026-04-02T18:42:30+00:00","modifiedAt":"2026-05-06T20:44:10.0258008+00:00","affected":[{"ecosystem":"Go","name":"github.com/flannel-io/flannel","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"0.28.2"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[],"references":["https://github.com/flannel-io/flannel/security/advisories/GHSA-vchx-5pr6-ffx2","https://nvd.nist.gov/vuln/detail/CVE-2026-32241","https://github.com/flannel-io/flannel/commit/08bc9a4c990ae785d2fcb448f4991b58485cd26a","https://github.com/flannel-io/flannel/releases/tag/v0.28.2"],"sourceUrl":"https://osv.dev/vulnerability/GO-2026-4894","license":"OSV · upstream source license applies","key":"osv:GO-2026-4894","identifiers":["GO-2026-4894","CVE-2026-32241","GHSA-vchx-5pr6-ffx2"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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