{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-47552 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-47552 is a high-severity vulnerability in Linux kernel, published on 24 May 2024. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2021-47552 and fix it if it is affected.\n\nWhat it is: CVE-2021-47552 is a high-severity vulnerability in Linux kernel, published on 24 May 2024. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2021-47552 in the wild and no public exploit code.\n\nAffected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2021-47552/ (Markdown: https://insights.sbomify.com/CVE-2021-47552/index.md)","id":"CVE-2021-47552","markdown":"https://insights.sbomify.com/CVE-2021-47552/index.md","name":"CVE-2021-47552","record":{"aliases":["DEBIAN-CVE-2021-47552","ROOT-OS-DEBIAN-11-CVE-2021-47552","UBUNTU-CVE-2021-47552"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A null pointer dereference in the Linux kernel block layer can cause a kernel panic, leading to denial of service.","user_interaction":"not_required","vuln_class":"null_dereference"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":7.8,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-476","name":"NULL Pointer Dereference"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nblk-mq: cancel blk-mq dispatch work in both blk_cleanup_queue and disk_release()\n\nFor avoiding to slow down queue destroy, we don't call\nblk_mq_quiesce_queue() in blk_cleanup_queue(), instead of delaying to\ncancel dispatch work in blk_release_queue().\n\nHowever, this way has caused kernel oops[1], reported by Changhui. The log\nshows that scsi_device can be freed before running blk_release_queue(),\nwhich is expected too since scsi_device is released after the scsi disk\nis closed and the scsi_device is removed.\n\nFixes the issue by canceling blk-mq dispatch work in both blk_cleanup_queue()\nand disk_release():\n\n1) when disk_release() is run, the disk has been closed, and any sync\ndispatch activities have been done, so canceling dispatch work is enough to\nquiesce filesystem I/O dispatch activity.\n\n2) in blk_cleanup_queue(), we only focus on passthrough request, and\npassthrough request is always explicitly allocated \u0026 freed by\nits caller, so once queue is frozen, all sync dispatch activity\nfor passthrough request has been done, then it is enough to just cancel\ndispatch work for avoiding any dispatch activity.\n\n[1] kernel panic log\n[12622.769416] BUG: kernel NULL pointer dereference, address: 0000000000000300\n[12622.777186] #PF: supervisor read access in kernel mode\n[12622.782918] #PF: error_code(0x0000) - not-present page\n[12622.788649] PGD 0 P4D 0\n[12622.791474] Oops: 0000 [#1] PREEMPT SMP PTI\n[12622.796138] CPU: 10 PID: 744 Comm: kworker/10:1H Kdump: loaded Not tainted 5.15.0+ #1\n[12622.804877] Hardware name: Dell Inc. PowerEdge R730/0H21J3, BIOS 1.5.4 10/002/2015\n[12622.813321] Workqueue: kblockd blk_mq_run_work_fn\n[12622.818572] RIP: 0010:sbitmap_get+0x75/0x190\n[12622.823336] Code: 85 80 00 00 00 41 8b 57 08 85 d2 0f 84 b1 00 00 00 45 31 e4 48 63 cd 48 8d 1c 49 48 c1 e3 06 49 03 5f 10 4c 8d 6b 40 83 f0 01 \u003c48\u003e 8b 33 44 89 f2 4c 89 ef 0f b6 c8 e8 fa f3 ff ff 83 f8 ff 75 58\n[12622.844290] RSP: 0018:ffffb00a446dbd40 EFLAGS: 00010202\n[12622.850120] RAX: 0000000000000001 RBX: 0000000000000300 RCX: 0000000000000004\n[12622.858082] RDX: 0000000000000006 RSI: 0000000000000082 RDI: ffffa0b7a2dfe030\n[12622.866042] RBP: 0000000000000004 R08: 0000000000000001 R09: ffffa0b742721334\n[12622.874003] R10: 0000000000000008 R11: 0000000000000008 R12: 0000000000000000\n[12622.881964] R13: 0000000000000340 R14: 0000000000000000 R15: ffffa0b7a2dfe030\n[12622.889926] FS:  0000000000000000(0000) GS:ffffa0baafb40000(0000) knlGS:0000000000000000\n[12622.898956] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[12622.905367] CR2: 0000000000000300 CR3: 0000000641210001 CR4: 00000000001706e0\n[12622.913328] Call Trace:\n[12622.916055]  \u003cTASK\u003e\n[12622.918394]  scsi_mq_get_budget+0x1a/0x110\n[12622.922969]  __blk_mq_do_dispatch_sched+0x1d4/0x320\n[12622.928404]  ? pick_next_task_fair+0x39/0x390\n[12622.933268]  __blk_mq_sched_dispatch_requests+0xf4/0x140\n[12622.939194]  blk_mq_sched_dispatch_requests+0x30/0x60\n[12622.944829]  __blk_mq_run_hw_queue+0x30/0xa0\n[12622.949593]  process_one_work+0x1e8/0x3c0\n[12622.954059]  worker_thread+0x50/0x3b0\n[12622.958144]  ? rescuer_thread+0x370/0x370\n[12622.962616]  kthread+0x158/0x180\n[12622.966218]  ? set_kthread_struct+0x40/0x40\n[12622.970884]  ret_from_fork+0x22/0x30\n[12622.974875]  \u003c/TASK\u003e\n[12622.977309] Modules linked in: scsi_debug rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache netfs sunrpc dm_multipath intel_rapl_msr intel_rapl_common dell_wmi_descriptor sb_edac rfkill video x86_pkg_temp_thermal intel_powerclamp dcdbas coretemp kvm_intel kvm mgag200 irqbypass i2c_algo_bit rapl drm_kms_helper ipmi_ssif intel_cstate intel_uncore syscopyarea sysfillrect sysimgblt fb_sys_fops pcspkr cec mei_me lpc_ich mei ipmi_si ipmi_devintf ipmi_msghandler acpi_power_meter drm fuse xfs libcrc32c sr_mod cdrom sd_mod t10_pi sg ixgbe ahci libahci crct10dif_pclmul crc32_pclmul crc32c_intel libata megaraid_sas ghash_clmulni_intel tg3 wdat_w\n---truncated---","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"blk-mq: cancel blk-mq dispatch work in both blk_cleanup_queue and disk_release()","id":"CVE-2021-47552","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"null_dereference","year":"2021"},"n_packages":0,"n_references":2,"next":{"headline":"sched/scs: Reset task stack state in bringup_cpu()","id":"CVE-2021-47553"},"packages":[],"prev":{"headline":"drm/amd/amdkfd: Fix kernel panic when reset failed and been triggered again","id":"CVE-2021-47551"},"products":["Linux"],"published":"2024-05-24","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-08-05","vendors":["Linux"]},"summary":"A null pointer dereference in the Linux kernel block layer can cause a kernel panic, leading to denial of service.","url":"https://insights.sbomify.com/CVE-2021-47552/"}