{"cve":"CVE-2021-46959","nvd":{"published":"2024-02-29T23:15:07.230","modified":"2026-06-17T04:15:59.303","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nspi: Fix use-after-free with devm_spi_alloc_*\n\nWe can't rely on the contents of the devres list during\nspi_unregister_controller(), as the list is already torn down at the\ntime we perform devres_find() for devm_spi_release_controller. This\ncauses devices registered with devm_spi_alloc_{master,slave}() to be\nmistakenly identified as legacy, non-devm managed devices and have their\nreference counters decremented below 0.\n\n------------[ cut here ]------------\nWARNING: CPU: 1 PID: 660 at lib/refcount.c:28 refcount_warn_saturate+0x108/0x174\n[<b0396f04>] (refcount_warn_saturate) from [<b03c56a4>] (kobject_put+0x90/0x98)\n[<b03c5614>] (kobject_put) from [<b0447b4c>] (put_device+0x20/0x24)\n r4:b6700140\n[<b0447b2c>] (put_device) from [<b07515e8>] (devm_spi_release_controller+0x3c/0x40)\n[<b07515ac>] (devm_spi_release_controller) from [<b045343c>] (release_nodes+0x84/0xc4)\n r5:b6700180 r4:b6700100\n[<b04533b8>] (release_nodes) from [<b0454160>] (devres_release_all+0x5c/0x60)\n r8:b1638c54 r7:b117ad94 r6:b1638c10 r5:b117ad94 r4:b163dc10\n[<b0454104>] (devres_release_all) from [<b044e41c>] (__device_release_driver+0x144/0x1ec)\n r5:b117ad94 r4:b163dc10\n[<b044e2d8>] (__device_release_driver) from [<b044f70c>] (device_driver_detach+0x84/0xa0)\n r9:00000000 r8:00000000 r7:b117ad94 r6:b163dc54 r5:b1638c10 r4:b163dc10\n[<b044f688>] (device_driver_detach) from [<b044d274>] (unbind_store+0xe4/0xf8)\n\nInstead, determine the devm allocation state as a flag on the\ncontroller which is guaranteed to be stable during cleanup.","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/001c8e83646ad3b847b18f6ac55a54367d917d74","https://git.kernel.org/stable/c/28a5529068c51cdf0295ab1e11a99a3a909a03e4","https://git.kernel.org/stable/c/62bb2c7f2411a0045c24831f11ecacfc35610815","https://git.kernel.org/stable/c/794aaf01444d4e765e2b067cba01cc69c1c68ed9","https://git.kernel.org/stable/c/8735248ebb918d25427965f0db07939ed0473ec6"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:46:54.846886191+00:00"},"epss":{"cve":"CVE-2021-46959","score":0.00245,"percentile":0.15829,"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."]}