{"id":"CVE-2025-39871","title":"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; u…","summary":"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; u…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-416"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 6.1.140, < 6.2","linux_kernel >= 6.6.92, < 6.6.107","linux_kernel >= 6.12.30, < 6.12.48","linux_kernel >= 6.14.8, < 6.15","linux_kernel >= 6.15.1, < 6.16.8","linux_kernel = 6.15","linux_kernel = 6.17"],"patched":["linux_kernel 6.16.8"],"published":"2025-09-23","updated":"2026-10-15","sourceUpdated":"2026-10-15T02:18:02.613","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-39871","references":[{"url":"https://git.kernel.org/stable/c/0e95ee7f532b21206fe3f1c4054002b0d21e3b9c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/24414bbcb37e1af95190af36c21ae51d497e1a9e","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/da4fbc1488a4cec6748da685181ee4449a878dac","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/dd7a7e43269711d757fc260b0bbdf7138f75de11","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f41c538881eec4dcf5961a242097d447f848cda6","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-457936.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org"],"epss":0.00154,"epssPercentile":0.04442,"ingestedAt":"2026-09-08T15:33:26.996Z","slug":"CVE-2025-39871","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `linux_kernel >= 6.1.140, < 6.2`\n- `linux_kernel >= 6.6.92, < 6.6.107`\n- `linux_kernel >= 6.12.30, < 6.12.48`\n- `linux_kernel >= 6.14.8, < 6.15`\n- `linux_kernel >= 6.15.1, < 6.16.8`\n- `linux_kernel = 6.15`\n- `linux_kernel = 6.17`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.16.8`","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":221559,"id":"CVE-2025-39871","ts":1792035261819,"field":"cvss","old":null,"new":"7.8"},{"seq":221558,"id":"CVE-2025-39871","ts":1792035261819,"field":"severity","old":"none","new":"high"}]}