{"id":"CVE-2026-23209","revision":"b8488e7ebac949d1855740a51fca749c","records":[{"revision":"b8488e7ebac949d1855740a51fca749c","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-23209","aliases":[],"title":"macvlan: fix error recovery in macvlan_common_newlink()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmacvlan: fix error recovery in macvlan_common_newlink()\n\nvalis provided a nice repro to crash the kernel:\n\nip link add p1 type veth peer p2\nip link set address 00:00:00:00:00:20 dev p1\nip link set up dev p1\nip link set up dev p2\n\nip link add mv0 link p2 type macvlan mode source\nip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20\n\nping -c1 -I p1 1.2.3.4\n\nHe also gave a very detailed analysis:\n\n\n\nThe issue is triggered when a new macvlan link is created with\nMACVLAN_MODE_SOURCE mode and MACVLAN_MACADDR_ADD (or\nMACVLAN_MACADDR_SET) parameter, lower device already has a macvlan\nport and register_netdevice() called from macvlan_common_newlink()\nfails (e.g. because of the invalid link name).\n\nIn this case macvlan_hash_add_source is called from\nmacvlan_change_sources() / macvlan_common_newlink():\n\nThis adds a reference to vlan to the port's vlan_source_hash using\nmacvlan_source_entry.\n\nvlan is a pointer to the priv data of the link that is being created.\n\nWhen register_netdevice() fails, the error is returned from\nmacvlan_newlink() to rtnl_newlink_create():\n\n if (ops->newlink)\n err = ops->newlink(dev, ¶ms, extack);\n else\n err = register_netdevice(dev);\n if (err < 0) {\n free_netdev(dev);\n goto out;\n }\n\nand free_netdev() is called, causing a kvfree() on the struct\nnet_device that is still referenced in the source entry attached to\nthe lower device's macvlan port.\n\nNow all packets sent on the macvlan port with a matching source mac\naddress will trigger a use-after-free in macvlan_forward_source().\n\n\n\nWith all that, my fix is to make sure we call macvlan_flush_sources()\nregardless of @create value whenever \"goto destroy_macvlan_port;\"\npath is taken.\n\nMany thanks to valis for following up on this issue.","state":0,"publishedAt":"2026-02-14T16:27:31.175+00:00","modifiedAt":"2026-10-19T18:35:38.702+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"unaffected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"drivers/net/macvlan.c\"\n ],\n \"versions\": [\n {\n \"version\": \"aa5fd0fb77486b8a6764ead8627baa14790e4280\",\n \"lessThan\": \"da5c6b8ae47e414be47e5e04def15b25d5c962dc\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"aa5fd0fb77486b8a6764ead8627baa14790e4280\",\n \"lessThan\": \"5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"aa5fd0fb77486b8a6764ead8627baa14790e4280\",\n \"lessThan\": \"c43d0e787cbba569ec9d11579ed370b50fab6c9c\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"aa5fd0fb77486b8a6764ead8627baa14790e4280\",\n \"lessThan\": \"11ba9f0dc865136174cb98834280fb21bbc950c7\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"aa5fd0fb77486b8a6764ead8627baa14790e4280\",\n \"lessThan\": \"986967a162142710076782d5b93daab93a892980\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"aa5fd0fb77486b8a6764ead8627baa14790e4280\",\n \"lessThan\": \"cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"aa5fd0fb77486b8a6764ead8627baa14790e4280\",\n \"lessThan\": \"f8db6475a83649689c087a8f52486fcc53e627e9\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n }\n ]\n }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"affected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"drivers/net/macvlan.c\"\n ],\n \"versions\": [\n {\n \"version\": \"4.9\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"4.9\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.10.250\",\n \"lessThanOrEqual\": \"5.10.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.200\",\n \"lessThanOrEqual\": \"5.15.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.163\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.124\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.70\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.10\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.19\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/da5c6b8ae47e414be47e5e04def15b25d5c962dc","https://git.kernel.org/stable/c/5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a","https://git.kernel.org/stable/c/c43d0e787cbba569ec9d11579ed370b50fab6c9c","https://git.kernel.org/stable/c/11ba9f0dc865136174cb98834280fb21bbc950c7","https://git.kernel.org/stable/c/986967a162142710076782d5b93daab93a892980","https://git.kernel.org/stable/c/cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66","https://git.kernel.org/stable/c/f8db6475a83649689c087a8f52486fcc53e627e9"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-23209","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-23209","identifiers":["CVE-2026-23209"]},"retained":false,"historicalAffected":[]}],"coverage":[]}