{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2021-47274","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-05-21T13:27:52.127Z","datePublished":"2024-05-21T14:20:02.694Z","dateUpdated":"2026-08-05T08:47:02.813Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T08:47:02.813Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Correct the length check which causes memory corruption\n\nWe've suffered from severe kernel crashes due to memory corruption on\nour production environment, like,\n\nCall Trace:\n[1640542.554277] general protection fault: 0000 [#1] SMP PTI\n[1640542.554856] CPU: 17 PID: 26996 Comm: python Kdump: loaded Tainted:G\n[1640542.556629] RIP: 0010:kmem_cache_alloc+0x90/0x190\n[1640542.559074] RSP: 0018:ffffb16faa597df8 EFLAGS: 00010286\n[1640542.559587] RAX: 0000000000000000 RBX: 0000000000400200 RCX:\n0000000006e931bf\n[1640542.560323] RDX: 0000000006e931be RSI: 0000000000400200 RDI:\nffff9a45ff004300\n[1640542.560996] RBP: 0000000000400200 R08: 0000000000023420 R09:\n0000000000000000\n[1640542.561670] R10: 0000000000000000 R11: 0000000000000000 R12:\nffffffff9a20608d\n[1640542.562366] R13: ffff9a45ff004300 R14: ffff9a45ff004300 R15:\n696c662f65636976\n[1640542.563128] FS:  00007f45d7c6f740(0000) GS:ffff9a45ff840000(0000)\nknlGS:0000000000000000\n[1640542.563937] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[1640542.564557] CR2: 00007f45d71311a0 CR3: 000000189d63e004 CR4:\n00000000003606e0\n[1640542.565279] DR0: 0000000000000000 DR1: 0000000000000000 DR2:\n0000000000000000\n[1640542.566069] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:\n0000000000000400\n[1640542.566742] Call Trace:\n[1640542.567009]  anon_vma_clone+0x5d/0x170\n[1640542.567417]  __split_vma+0x91/0x1a0\n[1640542.567777]  do_munmap+0x2c6/0x320\n[1640542.568128]  vm_munmap+0x54/0x70\n[1640542.569990]  __x64_sys_munmap+0x22/0x30\n[1640542.572005]  do_syscall_64+0x5b/0x1b0\n[1640542.573724]  entry_SYSCALL_64_after_hwframe+0x44/0xa9\n[1640542.575642] RIP: 0033:0x7f45d6e61e27\n\nJames Wang has reproduced it stably on the latest 4.19 LTS.\nAfter some debugging, we finally proved that it's due to ftrace\nbuffer out-of-bound access using a debug tool as follows:\n[   86.775200] BUG: Out-of-bounds write at addr 0xffff88aefe8b7000\n[   86.780806]  no_context+0xdf/0x3c0\n[   86.784327]  __do_page_fault+0x252/0x470\n[   86.788367]  do_page_fault+0x32/0x140\n[   86.792145]  page_fault+0x1e/0x30\n[   86.795576]  strncpy_from_unsafe+0x66/0xb0\n[   86.799789]  fetch_memory_string+0x25/0x40\n[   86.804002]  fetch_deref_string+0x51/0x60\n[   86.808134]  kprobe_trace_func+0x32d/0x3a0\n[   86.812347]  kprobe_dispatcher+0x45/0x50\n[   86.816385]  kprobe_ftrace_handler+0x90/0xf0\n[   86.820779]  ftrace_ops_assist_func+0xa1/0x140\n[   86.825340]  0xffffffffc00750bf\n[   86.828603]  do_sys_open+0x5/0x1f0\n[   86.832124]  do_syscall_64+0x5b/0x1b0\n[   86.835900]  entry_SYSCALL_64_after_hwframe+0x44/0xa9\n\ncommit b220c049d519 (\"tracing: Check length before giving out\nthe filter buffer\") adds length check to protect trace data\noverflow introduced in 0fc1b09ff1ff, seems that this fix can't prevent\noverflow entirely, the length check should also take the sizeof\nentry->array[0] into account, since this array[0] is filled the\nlength of trace data and occupy addtional space and risk overflow."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The overflow is in local ftrace filter buffering (trace_event_buffer_lock_reserve), reached after writing tracefs filter/kprobe/trigger controls and then generating a near-page-sized event; it is not reachable from network or adjacent-link packet processing alone.\nAC:L - An attacker who can configure a filtered/soft-disabled event fully controls record length (e.g., kprobe string fetch of a chosen path length, or other dynamic payloads) and can hit the vulnerable PAGE_SIZE-minus-header window reliably with no race outside their control.\nPR:L - Enabling the path needs only TRACE_MODE_WRITE (0640) access under tracefs DAC/LOCKDOWN_TRACEFS (no capable() gate), and worst reasonable deployments (Android/perfetto, ChromeOS, gid=tracing mounts) grant that write access to non-root tracing users, matching other filter/buffered-event scorings.\nUI:N - The attacker writes the filter/kprobe configuration and triggers the oversized event themselves; no separate victim action is required.\nS:U - The out-of-bounds write corrupts host kernel memory within the same OS security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - This is a confirmed out-of-bounds write past the per-CPU filter page that caused production heap corruption; per guidance, exploitable memory corruption is treated as enabling high confidentiality impact.\nI:H - Out-of-bounds write past the allocated filter page is scored Integrity High, and the reported follow-on corruption (e.g., GPF in allocator paths) shows the overflow can corrupt adjacent kernel state usable for write/control-flow primitives.\nA:H - The bug was reproduced as an out-of-bounds write and caused severe kernel crashes/GPFs in production, which is High availability impact under kernel CVSS guidance."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/trace.c"],"versions":[{"version":"2e584b1a02eeb860e286d39bc408b25ebc5ec844","lessThan":"edcce01e0e50840a9aa6a70baed21477bdd2c9f9","status":"affected","versionType":"git"},{"version":"e46d433754420b4d6513ca389403de88a0910279","lessThan":"2d598902799886d67947406f26ee8e5fd2ca097f","status":"affected","versionType":"git"},{"version":"0572fc6a510add9029b113239eaabf4b5bce8ec9","lessThan":"31ceae385556c37e4d286cb6378696448f566883","status":"affected","versionType":"git"},{"version":"a0997a86f5c0085e183ddee5fb72091d584d3d16","lessThan":"d63f00ec908b3be635ead5d6029cc94246e1f38d","status":"affected","versionType":"git"},{"version":"7c93d8cff582c459350d6f8906eea6e4cd60d959","lessThan":"43c32c22254b9328d7abb1c2b0f689dc67838e60","status":"affected","versionType":"git"},{"version":"b220c049d5196dd94d992dd2dc8cba1a5e6123bf","lessThan":"b16a249eca2230c2cd66fa1d4b94743bd9b6ef92","status":"affected","versionType":"git"},{"version":"b220c049d5196dd94d992dd2dc8cba1a5e6123bf","lessThan":"3e08a9f9760f4a70d633c328a76408e62d6f80a3","status":"affected","versionType":"git"},{"version":"4.9.258","lessThan":"4.9.273","status":"affected","versionType":"semver"},{"version":"4.14.222","lessThan":"4.14.237","status":"affected","versionType":"semver"},{"version":"4.19.177","lessThan":"4.19.195","status":"affected","versionType":"semver"},{"version":"5.4.99","lessThan":"5.4.126","status":"affected","versionType":"semver"},{"version":"5.10.17","lessThan":"5.10.44","status":"affected","versionType":"semver"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/trace.c"],"versions":[{"version":"5.11","status":"affected"},{"version":"0","lessThan":"5.11","status":"unaffected","versionType":"semver"},{"version":"4.9.273","lessThanOrEqual":"4.9.*","status":"unaffected","versionType":"semver"},{"version":"4.14.237","lessThanOrEqual":"4.14.*","status":"unaffected","versionType":"semver"},{"version":"4.19.195","lessThanOrEqual":"4.19.*","status":"unaffected","versionType":"semver"},{"version":"5.4.126","lessThanOrEqual":"5.4.*","status":"unaffected","versionType":"semver"},{"version":"5.10.44","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.12.11","lessThanOrEqual":"5.12.*","status":"unaffected","versionType":"semver"},{"version":"5.13","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.9.258","versionEndExcluding":"4.9.273"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.14.222","versionEndExcluding":"4.14.237"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.19.177","versionEndExcluding":"4.19.195"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.4.99","versionEndExcluding":"5.4.126"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.17","versionEndExcluding":"5.10.44"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"5.12.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"5.13"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/edcce01e0e50840a9aa6a70baed21477bdd2c9f9"},{"url":"https://git.kernel.org/stable/c/2d598902799886d67947406f26ee8e5fd2ca097f"},{"url":"https://git.kernel.org/stable/c/31ceae385556c37e4d286cb6378696448f566883"},{"url":"https://git.kernel.org/stable/c/d63f00ec908b3be635ead5d6029cc94246e1f38d"},{"url":"https://git.kernel.org/stable/c/43c32c22254b9328d7abb1c2b0f689dc67838e60"},{"url":"https://git.kernel.org/stable/c/b16a249eca2230c2cd66fa1d4b94743bd9b6ef92"},{"url":"https://git.kernel.org/stable/c/3e08a9f9760f4a70d633c328a76408e62d6f80a3"}],"title":"tracing: Correct the length check which causes memory corruption","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"problemTypes":[{"descriptions":[{"type":"CWE","cweId":"CWE-125","lang":"en","description":"CWE-125 Out-of-bounds Read"}]}],"affected":[{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"2e584b1a02ee","status":"affected","lessThan":"edcce01e0e50","versionType":"custom"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"e46d43375442","status":"affected","lessThan":"2d5989027998","versionType":"custom"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"0572fc6a510a","status":"affected","lessThan":"31ceae385556","versionType":"custom"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"a0997a86f5c0","status":"affected","lessThan":"d63f00ec908b","versionType":"custom"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"7c93d8cff582","status":"affected","lessThan":"43c32c22254b","versionType":"custom"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"b220c049d519","status":"affected","lessThan":"b16a249eca22","versionType":"custom"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"b220c049d519","status":"affected","lessThan":"3e08a9f9760f","versionType":"custom"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"5.11","status":"affected"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"0","status":"unaffected","lessThan":"5.11","versionType":"custom"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"4.9.273","status":"unaffected","lessThanOrEqual":"5.0","versionType":"custom"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"4.14.237","status":"unaffected","lessThanOrEqual":"4.15","versionType":"custom"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"4.19.195","status":"unaffected","lessThanOrEqual":"4.20","versionType":"custom"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"5.4.126","status":"unaffected","lessThanOrEqual":"5.5","versionType":"custom"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"5.10.44","status":"unaffected","lessThanOrEqual":"5.11","versionType":"custom"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"5.12.11","status":"unaffected","lessThanOrEqual":"5.13","versionType":"custom"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"5.13","status":"unaffected"}]}],"metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":9.8,"attackVector":"NETWORK","baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","integrityImpact":"HIGH","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"NONE","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"timestamp":"2024-06-06T18:18:56.660554Z","id":"CVE-2021-47274","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2024-06-06T18:44:15.427Z"}},{"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2024-08-04T05:32:07.995Z"},"title":"CVE Program Container","references":[{"url":"https://git.kernel.org/stable/c/edcce01e0e50840a9aa6a70baed21477bdd2c9f9","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/2d598902799886d67947406f26ee8e5fd2ca097f","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/31ceae385556c37e4d286cb6378696448f566883","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/d63f00ec908b3be635ead5d6029cc94246e1f38d","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/43c32c22254b9328d7abb1c2b0f689dc67838e60","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/b16a249eca2230c2cd66fa1d4b94743bd9b6ef92","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/3e08a9f9760f4a70d633c328a76408e62d6f80a3","tags":["x_transferred"]}]}]}}