{"id":"CVE-2025-39871","title":"dmaengine: idxd: Remove improper idxd_free","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":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 68ac5a01f635b3791196fd1c39bc48497252c36f < 24414bbcb37e1af95190af36c21ae51d497e1a9e","Linux >= d2d05fd0fc95c4defed6f7b87550e20e8baa1d97 < 0e95ee7f532b21206fe3f1c4054002b0d21e3b9c","Linux >= 21f9f5cd9a0c75084d4369ba0b8c4f695c41dea7 < dd7a7e43269711d757fc260b0bbdf7138f75de11","Linux >= d5449ff1b04dfe9ed8e455769aa01e4c2ccf6805 < da4fbc1488a4cec6748da685181ee4449a878dac","Linux >= d5449ff1b04dfe9ed8e455769aa01e4c2ccf6805 < f41c538881eec4dcf5961a242097d447f848cda6","Linux 2b7a961cea0e5b65afda911f76d14fec5c98d024","Linux >= 6.1.140 < 6.1.160","Linux >= 6.6.92 < 6.6.107","Linux >= 6.12.30 < 6.12.48","Linux >= 6.14.8 < 6.15","Linux 6.15"],"published":"2025-09-23","updated":"2026-09-08","sourceUpdated":"2026-09-08T08:42:31.718Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-39871","references":[{"url":"https://git.kernel.org/stable/c/24414bbcb37e1af95190af36c21ae51d497e1a9e"},{"url":"https://git.kernel.org/stable/c/0e95ee7f532b21206fe3f1c4054002b0d21e3b9c"},{"url":"https://git.kernel.org/stable/c/dd7a7e43269711d757fc260b0bbdf7138f75de11"},{"url":"https://git.kernel.org/stable/c/da4fbc1488a4cec6748da685181ee4449a878dac"},{"url":"https://git.kernel.org/stable/c/f41c538881eec4dcf5961a242097d447f848cda6"}],"tags":["cve.org"],"epss":0.0015,"epssPercentile":0.04577,"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 >= 68ac5a01f635b3791196fd1c39bc48497252c36f < 24414bbcb37e1af95190af36c21ae51d497e1a9e`\n- `Linux >= d2d05fd0fc95c4defed6f7b87550e20e8baa1d97 < 0e95ee7f532b21206fe3f1c4054002b0d21e3b9c`\n- `Linux >= 21f9f5cd9a0c75084d4369ba0b8c4f695c41dea7 < dd7a7e43269711d757fc260b0bbdf7138f75de11`\n- `Linux >= d5449ff1b04dfe9ed8e455769aa01e4c2ccf6805 < da4fbc1488a4cec6748da685181ee4449a878dac`\n- `Linux >= d5449ff1b04dfe9ed8e455769aa01e4c2ccf6805 < f41c538881eec4dcf5961a242097d447f848cda6`\n- `Linux 2b7a961cea0e5b65afda911f76d14fec5c98d024`\n- `Linux >= 6.1.140 < 6.1.160`\n- `Linux >= 6.6.92 < 6.6.107`\n- `Linux >= 6.12.30 < 6.12.48`\n- `Linux >= 6.14.8 < 6.15`\n- `Linux 6.15`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}