[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"repo-stars":3,"vuln-DEBIAN-CVE-2021-47566":6},{"stargazers_count":4,"fetched_at":5},7,"2026-06-04T08:53:30.047Z",{"id":7,"descriptions":8,"cisa":9,"weaknesses":10,"exploits":11,"aliases":12,"duplicate_of":9,"upstream":13,"downstream":16,"duplicates":17,"related":18,"reserved_at":9,"published_at":19,"modified_at":20,"state":9,"summary":21,"references_raw":23,"kevs":30,"epss":9,"epss_history":31,"metrics":32,"affected":39},"DEBIAN-CVE-2021-47566","In the Linux kernel, the following vulnerability has been resolved:  proc/vmcore: fix clearing user buffer by properly using clear_user()  To clear a user buffer we cannot simply use memset, we have to use clear_user().  With a virtio-mem device that registers a vmcore_cb and has some logically unplugged memory inside an added Linux memory block, I can easily trigger a BUG by copying the vmcore via \"cp\":    systemd[1]: Starting Kdump Vmcore Save Service...   kdump[420]: Kdump is using the default log level(3).   kdump[453]: saving to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/   kdump[458]: saving vmcore-dmesg.txt to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/   kdump[465]: saving vmcore-dmesg.txt complete   kdump[467]: saving vmcore   BUG: unable to handle page fault for address: 00007f2374e01000   #PF: supervisor write access in kernel mode   #PF: error_code(0x0003) - permissions violation   PGD 7a523067 P4D 7a523067 PUD 7a528067 PMD 7a525067 PTE 800000007048f867   Oops: 0003 [#1] PREEMPT SMP NOPTI   CPU: 0 PID: 468 Comm: cp Not tainted 5.15.0+ #6   Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-27-g64f37cc530f1-prebuilt.qemu.org 04/01/2014   RIP: 0010:read_from_oldmem.part.0.cold+0x1d/0x86   Code: ff ff ff e8 05 ff fe ff e9 b9 e9 7f ff 48 89 de 48 c7 c7 38 3b 60 82 e8 f1 fe fe ff 83 fd 08 72 3c 49 8d 7d 08 4c 89 e9 89 e8 \u003C49> c7 45 00 00 00 00 00 49 c7 44 05 f8 00 00 00 00 48 83 e7 f81   RSP: 0018:ffffc9000073be08 EFLAGS: 00010212   RAX: 0000000000001000 RBX: 00000000002fd000 RCX: 00007f2374e01000   RDX: 0000000000000001 RSI: 00000000ffffdfff RDI: 00007f2374e01008   RBP: 0000000000001000 R08: 0000000000000000 R09: ffffc9000073bc50   R10: ffffc9000073bc48 R11: ffffffff829461a8 R12: 000000000000f000   R13: 00007f2374e01000 R14: 0000000000000000 R15: ffff88807bd421e8   FS:  00007f2374e12140(0000) GS:ffff88807f000000(0000) knlGS:0000000000000000   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033   CR2: 00007f2374e01000 CR3: 000000007a4aa000 CR4: 0000000000350eb0   Call Trace:    read_vmcore+0x236/0x2c0    proc_reg_read+0x55/0xa0    vfs_read+0x95/0x190    ksys_read+0x4f/0xc0    do_syscall_64+0x3b/0x90    entry_SYSCALL_64_after_hwframe+0x44/0xae  Some x86-64 CPUs have a CPU feature called \"Supervisor Mode Access Prevention (SMAP)\", which is used to detect wrong access from the kernel to user buffers like this: SMAP triggers a permissions violation on wrong access.  In the x86-64 variant of clear_user(), SMAP is properly handled via clac()+stac().  To fix, properly use clear_user() when we're dealing with a user buffer.",null,[],[],[],[14],{"_key":15},"CVE-2021-47566",[],[],[],"2024-05-24T15:15:21.637Z","2026-04-28T20:23:32.087740Z",{"cisa_kev":22,"cisa_ransomware":22,"cisa_vendor":9,"epss_severity":9,"epss_score":9,"severity":9,"severity_score":9,"severity_version":9,"severity_source":9,"severity_vector":9,"severity_status":9},false,[24],{"url":25,"sources":26,"tags":28},"https://security-tracker.debian.org/tracker/CVE-2021-47566",[27],"osv_debian",[29],"Advisory",[],[],[33],{"source":27,"cvss_v2_0":9,"cvss_v3_0":9,"cvss_v3_1":34,"cvss_v4_0":9},{"baseScore":35,"baseSeverity":9,"vectorString":36,"impactScore":37,"exploitabilityScore":38},7.8,"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",9.8,4.6,[40],{"ecosystem":41,"name":42,"vendor":43,"product":42,"cpe_part":9,"purl_type":44,"purl_namespace":43,"purl_name":42,"source":9,"versions":45},"Debian","linux","debian","deb",[46,52,55,56],{"version":47,"is_range":48,"range_type":49,"version_start":9,"version_start_type":9,"version_end":50,"version_end_type":51,"fixed_in":9},"lt5_10_84_1",true,"ecosystem","5.10.84-1","excluding",{"version":53,"is_range":48,"range_type":49,"version_start":9,"version_start_type":9,"version_end":54,"version_end_type":51,"fixed_in":9},"lt5_15_15_1","5.15.15-1",{"version":53,"is_range":48,"range_type":49,"version_start":9,"version_start_type":9,"version_end":54,"version_end_type":51,"fixed_in":9},{"version":53,"is_range":48,"range_type":49,"version_start":9,"version_start_type":9,"version_end":54,"version_end_type":51,"fixed_in":9}]