{"id":"CVE-2025-39925","summary":"can: j1939: implement NETDEV_UNREGISTER notification handler","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ncan: j1939: implement NETDEV_UNREGISTER notification handler\n\nsyzbot is reporting\n\n  unregister_netdevice: waiting for vcan0 to become free. Usage count = 2\n\nproblem, for j1939 protocol did not have NETDEV_UNREGISTER notification\nhandler for undoing changes made by j1939_sk_bind().\n\nCommit 25fe97cb7620 (\"can: j1939: move j1939_priv_put() into sk_destruct\ncallback\") expects that a call to j1939_priv_put() can be unconditionally\ndelayed until j1939_sk_sock_destruct() is called. But we need to call\nj1939_priv_put() against an extra ref held by j1939_sk_bind() call\n(as a part of undoing changes made by j1939_sk_bind()) as soon as\nNETDEV_UNREGISTER notification fires (i.e. before j1939_sk_sock_destruct()\nis called via j1939_sk_release()). Otherwise, the extra ref on \"struct\nj1939_priv\" held by j1939_sk_bind() call prevents \"struct net_device\" from\ndropping the usage count to 1; making it impossible for\nunregister_netdevice() to continue.\n\n[mkl: remove space in front of label]","modified":"2026-03-20T12:43:06.309923Z","published":"2025-10-01T08:07:13.123Z","related":["ALSA-2025:22854","ALSA-2025:22865","CGA-5h9m-92rc-6gph","SUSE-SU-2025:03600-1","SUSE-SU-2025:03634-1","SUSE-SU-2025:20851-1","SUSE-SU-2025:20861-1","SUSE-SU-2025:20870-1","SUSE-SU-2025:20898-1","SUSE-SU-2025:21074-1","SUSE-SU-2025:21139-1","SUSE-SU-2025:21179-1","SUSE-SU-2025:3751-1","SUSE-SU-2025:4057-1","SUSE-SU-2025:4132-1","SUSE-SU-2025:4141-1","openSUSE-SU-2025:20081-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39925.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/7fcbe5b2c6a4b5407bf2241fdb71e0a390f6ab9a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/da9e8f429139928570407e8f90559b5d46c20262"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39925.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-39925"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"9d71dd0c70099914fcd063135da3c580865e924c"},{"fixed":"da9e8f429139928570407e8f90559b5d46c20262"},{"fixed":"7fcbe5b2c6a4b5407bf2241fdb71e0a390f6ab9a"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-39925.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}