{"id":"CVE-2024-40910","summary":"ax25: Fix refcount imbalance on inbound connections","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nax25: Fix refcount imbalance on inbound connections\n\nWhen releasing a socket in ax25_release(), we call netdev_put() to\ndecrease the refcount on the associated ax.25 device. However, the\nexecution path for accepting an incoming connection never calls\nnetdev_hold(). This imbalance leads to refcount errors, and ultimately\nto kernel crashes.\n\nA typical call trace for the above situation will start with one of the\nfollowing errors:\n\n    refcount_t: decrement hit 0; leaking memory.\n    refcount_t: underflow; use-after-free.\n\nAnd will then have a trace like:\n\n    Call Trace:\n    \u003cTASK\u003e\n    ? show_regs+0x64/0x70\n    ? __warn+0x83/0x120\n    ? refcount_warn_saturate+0xb2/0x100\n    ? report_bug+0x158/0x190\n    ? prb_read_valid+0x20/0x30\n    ? handle_bug+0x3e/0x70\n    ? exc_invalid_op+0x1c/0x70\n    ? asm_exc_invalid_op+0x1f/0x30\n    ? refcount_warn_saturate+0xb2/0x100\n    ? refcount_warn_saturate+0xb2/0x100\n    ax25_release+0x2ad/0x360\n    __sock_release+0x35/0xa0\n    sock_close+0x19/0x20\n    [...]\n\nOn reboot (or any attempt to remove the interface), the kernel gets\nstuck in an infinite loop:\n\n    unregister_netdevice: waiting for ax0 to become free. Usage count = 0\n\nThis patch corrects these issues by ensuring that we call netdev_hold()\nand ax25_dev_hold() for new connections in ax25_accept(). This makes the\nlogic leading to ax25_accept() match the logic for ax25_bind(): in both\ncases we increment the refcount, which is ultimately decremented in\nax25_release().","modified":"2026-04-02T12:17:19.768050Z","published":"2024-07-12T12:20:49.085Z","related":["SUSE-SU-2024:3194-1","SUSE-SU-2024:3195-1","SUSE-SU-2024:3225-1","SUSE-SU-2024:3227-1","SUSE-SU-2024:3249-1","SUSE-SU-2024:3383-1","SUSE-SU-2024:3408-1","SUSE-SU-2024:3569-1","SUSE-SU-2024:3587-1","SUSE-SU-2024:3592-1","SUSE-SU-2025:20044-1","SUSE-SU-2025:20047-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/40xxx/CVE-2024-40910.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/3c34fb0bd4a4237592c5ecb5b2e2531900c55774"},{"type":"WEB","url":"https://git.kernel.org/stable/c/52100fd74ad07b53a4666feafff1cd11436362d3"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a723a6c8d4831cc8e2c7b0c9f3f0c010d4671964"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f4df9d6c8d4e4c818252b0419c2165d66eabd4eb"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/40xxx/CVE-2024-40910.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-40910"},{"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":"9fd75b66b8f68498454d685dc4ba13192ae069b0"},{"fixed":"f4df9d6c8d4e4c818252b0419c2165d66eabd4eb"},{"fixed":"52100fd74ad07b53a4666feafff1cd11436362d3"},{"fixed":"a723a6c8d4831cc8e2c7b0c9f3f0c010d4671964"},{"fixed":"3c34fb0bd4a4237592c5ecb5b2e2531900c55774"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0"},{"last_affected":"c44a453ffe16eb08acdc6129ac4fa0192dbc0456"},{"last_affected":"de55a1338e6a48ff1e41ea8db1432496fbe2a62b"},{"last_affected":"9e1e088a57c23251f1cfe9601bbd90ade2ea73b9"},{"last_affected":"b20a5ab0f5fb175750c6bafd4cf12daccf00c738"},{"last_affected":"452ae92b99062d2f6a34324eaf705a3b7eac9f8b"},{"last_affected":"534156dd4ed768e30a43de0036f45dca7c54818f"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-40910.json"}}],"schema_version":"1.7.5"}