{"id":"CVE-2021-47481","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-47481","generatedAt":"2026-10-27T19:39:48.296Z","title":"In the Linux kernel, the following vulnerability has been resolved: RDMA/mlx5: Initialize the ODP xarray when creating an ODP MR Normally the zero fill would hide the missing initialization, but an errant set to desc_size in reg_create() causes a crash:…","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/mlx5: Initialize the ODP xarray when creating an ODP MR\n\nNormally the zero fill would hide the missing initialization, but an\nerrant set to desc_size in reg_create() causes a crash:\n\n  BUG: unable to handle page fault for address: 0000000800000000\n  PGD 0 P4D 0\n  Oops: 0000 [#1] SMP PTI\n  CPU: 5 PID: 890 Comm: ib_write_bw Not tainted 5.15.0-rc4+ #47\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014\n  RIP: 0010:mlx5_ib_dereg_mr+0x14/0x3b0 [mlx5_ib]\n  Code: 48 63 cd 4c 89 f7 48 89 0c 24 e8 37 30 03 e1 48 8b 0c 24 eb a0 90 0f 1f 44 00 00 41 56 41 55 41 54 55 53 48 89 fb 48 83 ec 30 <48> 8b 2f 65 48 8b 04 25 28 00 00 00 48 89 44 24 28 31 c0 8b 87 c8\n  RSP: 0018:ffff88811afa3a60 EFLAGS: 00010286\n  RAX: 000000000000001c RBX: 0000000800000000 RCX: 0000000000000000\n  RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000800000000\n  RBP: 0000000800000000 R08: 0000000000000000 R09: c0000000fffff7ff\n  R10: ffff88811afa38f8 R11: ffff88811afa38f0 R12: ffffffffa02c7ac0\n  R13: 0000000000000000 R14: ffff88811afa3cd8 R15: ffff88810772fa00\n  FS:  00007f47b9080740(0000) GS:ffff88852cd40000(0000) knlGS:0000000000000000\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  CR2: 0000000800000000 CR3: 000000010761e003 CR4: 0000000000370ea0\n  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n  Call Trace:\n   mlx5_ib_free_odp_mr+0x95/0xc0 [mlx5_ib]\n   mlx5_ib_dereg_mr+0x128/0x3b0 [mlx5_ib]\n   ib_dereg_mr_user+0x45/0xb0 [ib_core]\n   ? xas_load+0x8/0x80\n   destroy_hw_idr_uobject+0x1a/0x50 [ib_uverbs]\n   uverbs_destroy_uobject+0x2f/0x150 [ib_uverbs]\n   uobj_destroy+0x3c/0x70 [ib_uverbs]\n   ib_uverbs_cmd_verbs+0x467/0xb00 [ib_uverbs]\n   ? uverbs_finalize_object+0x60/0x60 [ib_uverbs]\n   ? ttwu_queue_wakelist+0xa9/0xe0\n   ? pty_write+0x85/0x90\n   ? file_tty_write.isra.33+0x214/0x330\n   ? process_echoes+0x60/0x60\n   ib_uverbs_ioctl+0xa7/0x110 [ib_uverbs]\n   __x64_sys_ioctl+0x10d/0x8e0\n   ? vfs_write+0x17f/0x260\n   do_syscall_64+0x3c/0x80\n   entry_SYSCALL_64_after_hwframe+0x44/0xae\n\nAdd the missing xarray initialization and remove the desc_size set.","published":"2024-05-22T09:15:10.000Z","lastModified":"2026-06-17T04:17:35.000Z","status":"Analyzed","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":5.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"cwe":[],"affected":["linux/linux kernel"],"epss":{"score":0.0018,"percentile":0.07524,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.18%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/5508546631a0f555d7088203dec2614e41b5106e","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5f6995295f65d1ee6f36d466d26afd98eb797afe","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5508546631a0f555d7088203dec2614e41b5106e","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/5f6995295f65d1ee6f36d466d26afd98eb797afe","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-47481","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}