{"cve":"CVE-2025-39721","nvd":{"published":"2025-09-05T18:15:49.770","modified":"2026-10-19T21:10:00.160","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto: qat - flush misc workqueue during device shutdown\n\nRepeated loading and unloading of a device specific QAT driver, for\nexample qat_4xxx, in a tight loop can lead to a crash due to a\nuse-after-free scenario. This occurs when a power management (PM)\ninterrupt triggers just before the device-specific driver (e.g.,\nqat_4xxx.ko) is unloaded, while the core driver (intel_qat.ko) remains\nloaded.\n\nSince the driver uses a shared workqueue (`qat_misc_wq`) across all\ndevices and owned by intel_qat.ko, a deferred routine from the\ndevice-specific driver may still be pending in the queue. If this\nroutine executes after the driver is unloaded, it can dereference freed\nmemory, resulting in a page fault and kernel crash like the following:\n\n    BUG: unable to handle page fault for address: ffa000002e50a01c\n    #PF: supervisor read access in kernel mode\n    RIP: 0010:pm_bh_handler+0x1d2/0x250 [intel_qat]\n    Call Trace:\n      pm_bh_handler+0x1d2/0x250 [intel_qat]\n      process_one_work+0x171/0x340\n      worker_thread+0x277/0x3a0\n      kthread+0xf0/0x120\n      ret_from_fork+0x2d/0x50\n\nTo prevent this, flush the misc workqueue during device shutdown to\nensure that all pending work items are completed before the driver is\nunloaded.\n\nNote: This approach may slightly increase shutdown latency if the\nworkqueue contains jobs from other devices, but it ensures correctness\nand stability.","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":["CWE-416"],"references":["https://git.kernel.org/stable/c/3d4df408ba9bad2b205c7fb8afc1836a6a4ca88a","https://git.kernel.org/stable/c/5858448a6c65d8ee3f8600570d3ce19febcb33be","https://git.kernel.org/stable/c/e59a52e429e13df3feb34f4853a8e36d121ed937","https://git.kernel.org/stable/c/fa4c14a82747886d333d8baef0d26da86ba1ccf7","https://git.kernel.org/stable/c/fe546f5c50fc474daca6bee72caa7ab68a74c33d"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-21T03:43:09.190223697+00:00"},"epss":{"cve":"CVE-2025-39721","score":0.00146,"percentile":0.03815,"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."]}