{"id":"CVE-2022-50488","title":"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: KA…","summary":"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: KA…","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 >= 5.4.198, < 5.5","linux_kernel >= 5.10.121, < 5.10.175","linux_kernel >= 5.15.46, < 5.15.86","linux_kernel >= 5.17.14, < 5.18","linux_kernel >= 5.18.3, < 6.0.16","linux_kernel >= 6.1, < 6.1.2"],"patched":["linux_kernel 6.1.2"],"published":"2025-10-04","updated":"2026-10-15","sourceUpdated":"2026-10-15T22:17:31.013","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2022-50488","references":[{"url":"https://git.kernel.org/stable/c/094f3d9314d67691cb21ba091c1b528f6e3c4893","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5533742c7cb1bc9b1f0bf401cc397d44a3a9e07a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/64dc8c732f5c2b406cc752e6aaa1bd5471159cab","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/761564d93c8265f65543acf0a576b32d66bfa26a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b22fd72bfebda3956efc4431b60ddfc0a51e03e0","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"epss":0.00166,"epssPercentile":0.05833,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-15T21:31:16.750641Z"},"ingestedAt":"2026-10-15T22:48:25.376Z","slug":"CVE-2022-50488","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `linux_kernel >= 5.4.198, < 5.5`\n- `linux_kernel >= 5.10.121, < 5.10.175`\n- `linux_kernel >= 5.15.46, < 5.15.86`\n- `linux_kernel >= 5.17.14, < 5.18`\n- `linux_kernel >= 5.18.3, < 6.0.16`\n- `linux_kernel >= 6.1, < 6.1.2`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.1.2`","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}