{"cve":"CVE-2025-39871","nvd":{"published":"2025-09-23T06:15:46.400","modified":"2026-10-19T21:10:00.160","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ndmaengine: idxd: Remove improper idxd_free\n\nThe call to idxd_free() introduces a duplicate put_device() leading to a\nreference count underflow:\nrefcount_t: underflow; use-after-free.\nWARNING: CPU: 15 PID: 4428 at lib/refcount.c:28 refcount_warn_saturate+0xbe/0x110\n...\nCall Trace:\n <TASK>\n  idxd_remove+0xe4/0x120 [idxd]\n  pci_device_remove+0x3f/0xb0\n  device_release_driver_internal+0x197/0x200\n  driver_detach+0x48/0x90\n  bus_remove_driver+0x74/0xf0\n  pci_unregister_driver+0x2e/0xb0\n  idxd_exit_module+0x34/0x7a0 [idxd]\n  __do_sys_delete_module.constprop.0+0x183/0x280\n  do_syscall_64+0x54/0xd70\n  entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nThe idxd_unregister_devices() which is invoked at the very beginning of\nidxd_remove(), already takes care of the necessary put_device() through the\nfollowing call path:\nidxd_unregister_devices() -> device_unregister() -> put_device()\n\nIn addition, when CONFIG_DEBUG_KOBJECT_RELEASE is enabled, put_device() may\ntrigger asynchronous cleanup via schedule_delayed_work(). If idxd_free() is\ncalled immediately after, it can result in a use-after-free.\n\nRemove the improper idxd_free() to avoid both the refcount underflow and\npotential memory corruption during module unload.","cvss_v4":null,"cvss_v3":{"version":"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},"cwes":["CWE-416"],"references":["https://git.kernel.org/stable/c/0e95ee7f532b21206fe3f1c4054002b0d21e3b9c","https://git.kernel.org/stable/c/24414bbcb37e1af95190af36c21ae51d497e1a9e","https://git.kernel.org/stable/c/da4fbc1488a4cec6748da685181ee4449a878dac","https://git.kernel.org/stable/c/dd7a7e43269711d757fc260b0bbdf7138f75de11","https://git.kernel.org/stable/c/f41c538881eec4dcf5961a242097d447f848cda6"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-21T03:43:09.190223697+00:00"},"epss":{"cve":"CVE-2025-39871","score":0.00154,"percentile":0.0444,"date":"2026-10-25"},"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."]}