{"id":"CVE-2025-39925","url":"https://www.cyber-defence.io/tools/cve/CVE-2025-39925","generatedAt":"2026-10-28T02:24:56.307Z","title":"In the Linux kernel, the following vulnerability has been resolved: can: j1939: implement NETDEV_UNREGISTER notification handler syzbot is reporting unregister_netdevice: waiting for vcan0 to become free.","description":"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]","published":"2025-10-01T08:15:36.000Z","lastModified":"2026-10-19T21:10:00.000Z","status":"Modified","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":5.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"cwe":[],"affected":["linux/linux kernel"],"epss":{"score":0.0015,"percentile":0.04119,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.15%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/2c88069fac2c792e228e6a4ae71c9b9b5b9a87a6","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/479d8a2aedcc1db16f14c1a8a9c74b5bdf18b9ac","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/4e154cb5e7681c2910e2dfa09f05e3469e333745","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/76957b618ce729c3bd1e782fbc9d9991af653925","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7fcbe5b2c6a4b5407bf2241fdb71e0a390f6ab9a","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/da9e8f429139928570407e8f90559b5d46c20262","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2025-39925","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}