Home/CVE/In the Linux kernel, the following vulnerability has been resolved: tracing: Correct the length check which causes memo
CVE

CVE-2021-47274

In the Linux kernel, the following vulnerability has been resolved: tracing: Correct the length check which causes memo

In the Linux kernel, the following vulnerability has been resolved: tracing: Correct the length check which causes memory corruption We've suffered from severe kernel crashes due to memory corruption on our production environment, like, Call Trace: [1640542.554277] general protection fault: 0000 [#1] SMP PTI [1640542.554856] CPU: 17 PID: 26996 Comm: python Kdump: loaded Tainted:G [1640542.556629] RIP: 0010:kmem_cache_alloc+0x90/0x190 [1640542.559074] RSP: 0018:ffffb16faa597df8 EFLAGS: 00010286 [1640542.559587] RAX: 0000000000000000 RBX: 0000000000400200 RCX: 0000000006e931bf [1640542.560323] RDX: 0000000006e931be RSI: 0000000000400200 RDI: ffff9a45ff004300 [1640542.560996] RBP: 0000000000400200 R08: 0000000000023420 R09: 0000000000000000 [1640542.561670] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff9a20608d [1640542.562366] R13: ffff9a45ff004300 R14: ffff9a45ff004300 R15: 696c662f65636976 [1640542.563128] FS: 00007f45d7c6f740(0000) GS:ffff9a45ff840000(0000) knlGS:0000000000000000 [1640542.563937] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [1640542.564557] CR2: 00007f45d71311a0 CR3: 000000189d63e004 CR4: 00000000003606e0 [1640542.565279] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [1640542.566069] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [1640542.566742] Call Trace: [1640542.567009] anon_vma_clone+0x5d/0x170 [1640542.567417] __split_vma+0x91/0x1a0 [1640542.567777] do_munmap+0x2c6/0x320 [1640542.568128] vm_munmap+0x54/0x70 [1640542.569990] __x64_sys_munmap+0x22/0x30 [1640542.572005] do_syscall_64+0x5b/0x1b0 [1640542.573724] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [1640542.575642] RIP: 0033:0x7f45d6e61e27 James Wang has reproduced it stably on the latest 4.19 LTS. After some debugging, we finally proved that it's due to ftrace buffer out-of-bound access using a debug tool as follows: [ 86.775200] BUG: Out-of-bounds write at addr 0xffff88aefe8b7000 [ 86.780806] no_context+0xdf/0x3c0 [ 86.784327] __do_page_fault+0x252/0x470 [ 86.788367] do_page_fault+0x32/0x140 [ 86.792145] page_fault+0x1e/0x30 [ 86.795576] strncpy_from_unsafe+0x66/0xb0 [ 86.799789] fetch_memory_string+0x25/0x40 [ 86.804002] fetch_deref_string+0x51/0x60 [ 86.808134] kprobe_trace_func+0x32d/0x3a0 [ 86.812347] kprobe_dispatcher+0x45/0x50 [ 86.816385] kprobe_ftrace_handler+0x90/0xf0 [ 86.820779] ftrace_ops_assist_func+0xa1/0x140 [ 86.825340] 0xffffffffc00750bf [ 86.828603] do_sys_open+0x5/0x1f0 [ 86.832124] do_syscall_64+0x5b/0x1b0 [ 86.835900] entry_SYSCALL_64_after_hwframe+0x44/0xa9 commit b220c049d519 ("tracing: Check length before giving out the filter buffer") adds length check to protect trace data overflow introduced in 0fc1b09ff1ff, seems that this fix can't prevent overflow entirely, the length check should also take the sizeof entry-array[0] into account, since this array[0] is filled the length of trace data and occupy addtional space and risk overflow.

CRITICAL · CVSS 9.8 EPSS 0.0006
Schedule remediation
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
Look this up elsewhere - one-click external pivots
NVDCVE.orgCISAVulnersExploit-DBGitHub PoCVulnCheck KEVGreyNoise
▸ How to read a CVE - triage first, then detect and patch
This page is every public fact about CVE-2021-47274, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.
Triage: should I act now? Four signals, and they are not interchangeable:
CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked. EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal. CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score. Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.
How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.
Then what - two workflows:
Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits. PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.
Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).
◆

ATT&CK techniques

1

Techniques this CVE enables - linked via CWECAPECATT&CK. High◆ = named directly in ATT&CK or Nuclei templates.

T1190 · Exploit Public-Facing Application
▤ Build a SIEM detection for these techniques
▤

CAPEC attack patterns

1

Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.

CAPEC-CAPEC-540 · Overread Buffers
⬡

Weakness Classification

CWE-125Out-of-bounds Read
▤

Affected Products & Versions

7
linux kernel>= 4.9.258 and < 4.9.273
linux kernel>= 4.14.222 and < 4.14.237
linux kernel>= 4.19.177 and < 4.19.195
linux kernel>= 5.4.99 and < 5.4.126
linux kernel>= 5.10.17 and < 5.10.44
linux kernel>= 5.11 and < 5.12.11
linux kernelall versions
▤

Affected Packages

40
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
Ubuntu:14.04:LTS linux fixed in 3.11.0-12.19
Ubuntu:14.04:LTS linux-aws fixed in 4.4.0-1002.2
Ubuntu:14.04:LTS linux-azure fixed in 4.15.0-1023.24~14.04.1
Ubuntu:14.04:LTS linux-lts-xenial fixed in 4.4.0-13.29~14.04.1
Ubuntu:16.04:LTS linux fixed in 4.4.0-2.16
Ubuntu:16.04:LTS linux-aws fixed in 4.4.0-1001.10
Ubuntu:16.04:LTS linux-aws-hwe fixed in 4.15.0-1030.31~16.04.1
Ubuntu:16.04:LTS linux-azure fixed in 4.11.0-1009.9
Ubuntu:16.04:LTS linux-gcp fixed in 4.10.0-1004.4
Ubuntu:16.04:LTS linux-hwe fixed in 4.8.0-39.42~16.04.1
Ubuntu:16.04:LTS linux-kvm fixed in 4.4.0-1004.9
Ubuntu:16.04:LTS linux-oracle fixed in 4.15.0-1007.9~16.04.1
Ubuntu:18.04:LTS linux fixed in 4.15.0-156.163
Ubuntu:18.04:LTS linux-aws fixed in 4.15.0-1111.118
Ubuntu:18.04:LTS linux-aws-5.4 fixed in 5.4.0-1055.58~18.04.1
Ubuntu:18.04:LTS linux-azure-4.15 fixed in 4.15.0-1123.136
Ubuntu:18.04:LTS linux-azure-5.4 fixed in 5.4.0-1056.58~18.04.1
Ubuntu:18.04:LTS linux-gcp-4.15 fixed in 4.15.0-1108.122
Ubuntu:18.04:LTS linux-gcp-5.4 fixed in 5.4.0-1051.55~18.04.1
Ubuntu:18.04:LTS linux-hwe-5.4 fixed in 5.4.0-81.91~18.04.1
Ubuntu:18.04:LTS linux-hwe-edge fixed in 5.0.0-15.16~18.04.1
Ubuntu:18.04:LTS linux-ibm-5.4 fixed in 5.4.0-1010.11~18.04.2
Ubuntu:18.04:LTS linux-kvm fixed in 4.15.0-1099.101
Ubuntu:18.04:LTS linux-oracle fixed in 4.15.0-1080.88
Ubuntu:18.04:LTS linux-oracle-5.4 fixed in 5.4.0-1053.57~18.04.1
Ubuntu:18.04:LTS linux-raspi-5.4 fixed in 5.4.0-1042.46~18.04.3
Ubuntu:20.04:LTS linux fixed in 5.4.0-81.91
Ubuntu:20.04:LTS linux-aws fixed in 5.4.0-1055.58
Ubuntu:20.04:LTS linux-aws-5.11
Ubuntu:20.04:LTS linux-aws-5.13
Ubuntu:20.04:LTS linux-aws-5.15 fixed in 5.15.0-1014.18~20.04.1
Ubuntu:20.04:LTS linux-aws-5.8
Ubuntu:20.04:LTS linux-azure fixed in 5.4.0-1056.58
Ubuntu:20.04:LTS linux-azure-5.11
Ubuntu:20.04:LTS linux-azure-5.13
Ubuntu:20.04:LTS linux-azure-5.15 fixed in 5.15.0-1007.8~20.04.1
Ubuntu:20.04:LTS linux-azure-5.8
Ubuntu:20.04:LTS linux-azure-fde
Ubuntu:20.04:LTS linux-azure-fde-5.15 fixed in 5.15.0-1019.24~20.04.1.1
Ubuntu:20.04:LTS linux-bluefield fixed in 5.4.0-1019.22
📦

Fixed versions by distribution

17
The package version that resolves this CVE on each Linux distribution, from the vendor’s published security data. fixed in shows a patched version exists; open means the package is listed as affected with no fix yet.
suse sle15kernel-64kb fixed in 0:5.3.18-150300.59.164.1
suse sle15kernel-default fixed in 0:5.3.18-150300.59.164.1
suse sle15kernel-default-base fixed in 0:5.3.18-150300.59.164.1.150300.18.96.1
suse sle15kernel-default-devel open
suse sle15kernel-default-livepatch fixed in 0:5.3.18-150200.24.194.1
suse sle15kernel-default-man open
suse sle15kernel-devel open
suse sle15kernel-docs fixed in 0:5.3.18-150300.59.164.1
suse sle15kernel-livepatch-5_3_18-150200_24_194-default fixed in 0:1-150200.5.3.1
suse sle15kernel-livepatch-5_3_18-150300_59_164-default fixed in 0:1-150300.7.3.1
suse sle15kernel-macros open
suse sle15kernel-obs-build fixed in 0:5.3.18-150300.59.164.1
suse sle15kernel-preempt fixed in 0:5.3.18-150200.24.194.1
suse sle15kernel-source fixed in 0:5.3.18-150200.24.194.1
suse sle15kernel-syms fixed in 0:5.3.18-150200.24.194.1
suse sle15kernel-zfcpdump fixed in 0:5.3.18-150300.59.164.1
suse sle15reiserfs-kmp-default fixed in 0:5.3.18-150300.59.164.1
▣

Scoring & Timeline

9.8
CRITICAL · CVSS v3.1 · 416baaa9-dc9f-4396-8d5f-8c081fb06d67
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD21 May 2024 · 03:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
yes
Technical impact
total
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

6
suse-csafSUSE-SU-2024:2183-1
suse-csafSUSE-SU-2024:2184-1
suse-csafSUSE-SU-2024:2185-1
suse-csafSUSE-SU-2024:2010-1
suse-csafSUSE-SU-2024:1979-1
🔗

References & Sources

7
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://git.kernel.org/stable/c/2d598902799886d67947406f26ee8e5fd2ca097fPatch
https://git.kernel.org/stable/c/31ceae385556c37e4d286cb6378696448f566883Patch
https://git.kernel.org/stable/c/3e08a9f9760f4a70d633c328a76408e62d6f80a3Patch
https://git.kernel.org/stable/c/43c32c22254b9328d7abb1c2b0f689dc67838e60Patch
https://git.kernel.org/stable/c/b16a249eca2230c2cd66fa1d4b94743bd9b6ef92Patch
https://git.kernel.org/stable/c/d63f00ec908b3be635ead5d6029cc94246e1f38dPatch
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