{"cve":"CVE-2024-40910","nvd":{"published":"2024-07-12T13:15:14.213","modified":"2026-08-04T11:19:04.370","status":"Modified","description":"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    <TASK>\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().","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":[],"references":["https://git.kernel.org/stable/c/3c34fb0bd4a4237592c5ecb5b2e2531900c55774","https://git.kernel.org/stable/c/52100fd74ad07b53a4666feafff1cd11436362d3","https://git.kernel.org/stable/c/a723a6c8d4831cc8e2c7b0c9f3f0c010d4671964","https://git.kernel.org/stable/c/f4df9d6c8d4e4c818252b0419c2165d66eabd4eb","https://git.kernel.org/stable/c/3c34fb0bd4a4237592c5ecb5b2e2531900c55774"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:52:42.518321223+00:00"},"epss":{"cve":"CVE-2024-40910","score":0.00446,"percentile":0.38834,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}