{"cve":"CVE-2022-50488","nvd":{"published":"2025-10-04T16:15:45.707","modified":"2026-10-15T22:17:31.013","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nblock, bfq: fix possible uaf for 'bfqq->bic'\n\nOur test report a uaf for 'bfqq->bic' in 5.10:\n\n==================================================================\nBUG: KASAN: use-after-free in bfq_select_queue+0x378/0xa30\n\nCPU: 6 PID: 2318352 Comm: fsstress Kdump: loaded Not tainted 5.10.0-60.18.0.50.h602.kasan.eulerosv2r11.x86_64 #1\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58-20220320_160524-szxrtosci10000 04/01/2014\nCall Trace:\n bfq_select_queue+0x378/0xa30\n bfq_dispatch_request+0xe8/0x130\n blk_mq_do_dispatch_sched+0x62/0xb0\n __blk_mq_sched_dispatch_requests+0x215/0x2a0\n blk_mq_sched_dispatch_requests+0x8f/0xd0\n __blk_mq_run_hw_queue+0x98/0x180\n __blk_mq_delay_run_hw_queue+0x22b/0x240\n blk_mq_run_hw_queue+0xe3/0x190\n blk_mq_sched_insert_requests+0x107/0x200\n blk_mq_flush_plug_list+0x26e/0x3c0\n blk_finish_plug+0x63/0x90\n __iomap_dio_rw+0x7b5/0x910\n iomap_dio_rw+0x36/0x80\n ext4_dio_read_iter+0x146/0x190 [ext4]\n ext4_file_read_iter+0x1e2/0x230 [ext4]\n new_sync_read+0x29f/0x400\n vfs_read+0x24e/0x2d0\n ksys_read+0xd5/0x1b0\n do_syscall_64+0x33/0x40\n entry_SYSCALL_64_after_hwframe+0x61/0xc6\n\nCommit 3bc5e683c67d (\"bfq: Split shared queues on move between cgroups\")\nchanges that move process to a new cgroup will allocate a new bfqq to\nuse, however, the old bfqq and new bfqq can point to the same bic:\n\n1) Initial state, two process with io in the same cgroup.\n\nProcess 1       Process 2\n (BIC1)          (BIC2)\n  |  Λ            |  Λ\n  |  |            |  |\n  V  |            V  |\n  bfqq1           bfqq2\n\n2) bfqq1 is merged to bfqq2.\n\nProcess 1       Process 2\n (BIC1)          (BIC2)\n  |               |\n   \\-------------\\|\n                  V\n  bfqq1           bfqq2(coop)\n\n3) Process 1 exit, then issue new io(denoce IOA) from Process 2.\n\n (BIC2)\n  |  Λ\n  |  |\n  V  |\n  bfqq2(coop)\n\n4) Before IOA is completed, move Process 2 to another cgroup and issue io.\n\nProcess 2\n (BIC2)\n   Λ\n   |\\--------------\\\n   |                V\n  bfqq2           bfqq3\n\nNow that BIC2 points to bfqq3, while bfqq2 and bfqq3 both point to BIC2.\nIf all the requests are completed, and Process 2 exit, BIC2 will be\nfreed while there is no guarantee that bfqq2 will be freed before BIC2.\n\nFix the problem by clearing bfqq->bic while bfqq is detached from bic.","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/094f3d9314d67691cb21ba091c1b528f6e3c4893","https://git.kernel.org/stable/c/5533742c7cb1bc9b1f0bf401cc397d44a3a9e07a","https://git.kernel.org/stable/c/64dc8c732f5c2b406cc752e6aaa1bd5471159cab","https://git.kernel.org/stable/c/761564d93c8265f65543acf0a576b32d66bfa26a","https://git.kernel.org/stable/c/b22fd72bfebda3956efc4431b60ddfc0a51e03e0"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:11:26.888974865+00:00"},"epss":{"cve":"CVE-2022-50488","score":0.00166,"percentile":0.05833,"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."]}