tracing: Correct the length check which causes memory corruption
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 1 without a fix
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 4.9.258 to before 4.9.273; 4.14.222 to before 4.14.237; 4.19.177 to before 4.19.195; 5.4.99 to before 5.4.126; 5.10.17 to before 5.10.44 | 4.9.273, 4.14.237, 4.19.195, 5.4.126, 5.10.44 | Patch available | CNA |
| Linux | Linux | 5.11 and later | 4.9.273, 4.14.237, 4.19.195, 5.4.126, 5.10.44, 5.12.11, 5.13 | Patch available | CNA |
- Linux VendorLinux Affected 4.9.258 to before 4.9.273; 4.14.222 to before 4.14.237; 4.19.177 to before 4.19.195; 5.4.99 to before 5.4.126; 5.10.17 to before 5.10.44 Fixed in 4.9.273, 4.14.237, 4.19.195, 5.4.126, 5.10.44 Patch available CNA
- Linux VendorLinux Affected 5.11 and later Fixed in 4.9.273, 4.14.237, 4.19.195, 5.4.126, 5.10.44, 5.12.11, 5.13 Patch available CNA
CPE configurations NVD · 6
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 4.9.258 to before 4.9.273; 4.14.222 to before 4.14.237; 4.19.177 to before 4.19.195; 5.4.99 to before 5.4.126; 5.10.17 to before 5.10.44; 5.11 to before 5.12.11 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:* | 5.13 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:* | 5.13 rc2 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:* | 5.13 rc3 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:* | 5.13 rc4 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.13:rc5:*:*:*:*:*:* | 5.13 rc5 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 4.9.258 to before 4.9.273; 4.14.222 to before 4.14.237; 4.19.177 to before 4.19.195; 5.4.99 to before 5.4.126; 5.10.17 to before 5.10.44; 5.11 to before 5.12.11 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:* Versions 5.13 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:* Versions 5.13 rc2 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:* Versions 5.13 rc3 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:* Versions 5.13 rc4 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.13:rc5:*:*:*:*:*:* Versions 5.13 rc5 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 4.9.273, 4.14.237, 4.19.195, 5.4.126, 5.10.44
- Fix · CNA Linux (Linux) Fixed in 4.9.273, 4.14.237, 4.19.195, 5.4.126, 5.10.44, 5.12.11, 5.13
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Out of support scope |
Not affected: 3 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2021-47274
- 2026-10-03 Alias added: GHSA-px85-vjfw-cm92
References
Patch 7
- https://git.kernel.org/stable/c/edcce01e0e50840a9aa6a70baed21477bdd2c9f9
- https://git.kernel.org/stable/c/2d598902799886d67947406f26ee8e5fd2ca097f
- https://git.kernel.org/stable/c/31ceae385556c37e4d286cb6378696448f566883
- https://git.kernel.org/stable/c/d63f00ec908b3be635ead5d6029cc94246e1f38d
- https://git.kernel.org/stable/c/43c32c22254b9328d7abb1c2b0f689dc67838e60
- https://git.kernel.org/stable/c/b16a249eca2230c2cd66fa1d4b94743bd9b6ef92
- https://git.kernel.org/stable/c/3e08a9f9760f4a70d633c328a76408e62d6f80a3
More Linux Kernel vulnerabilities
- TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
- TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2021-47274 · CVE Program
- CVE-2021-47274 · NVD
- FIRST EPSS
- GHSA-px85-vjfw-cm92 · GitHub Advisory Database · CC BY 4.0
- CVE-2021-47274 · Red Hat security data · CC BY 4.0
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