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TI-2021-22032 Aliases CVE-2021-47375GHSA-x6vg-gvf6-hmp9

blktrace: Fix uaf in blk_trace access after removing by sysfs

Priority LOW 27CWE-416Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · None · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA.

Summary

In the Linux kernel, the following vulnerability has been resolved: blktrace: Fix uaf in blk_trace access after removing by sysfs There is an use-after-free problem triggered by following process: P1(sda) P2(sdb) echo 0 > /sys/block/sdb/trace/enable blk_trace_remove_queue synchronize_rcu blk_trace_free relay_close rcu_read_lock __blk_add_trace trace_note_tsk (Iterate running_trace_list) relay_close_buf relay_destroy_buf kfree(buf) trace_note(sdb's bt) relay_reserve buf->offset <- nullptr deference (use-after-free) !!! rcu_read_unlock [ 502.714379] BUG: kernel NULL pointer dereference, address: 0000000000000010 [ 502.715260] #PF: supervisor read access in kernel mode [ 502.715903] #PF: error_code(0x0000) - not-present page [ 502.716546] PGD 103984067 P4D 103984067 PUD 17592b067 PMD 0 [ 502.717252] Oops: 0000 [#1] SMP [ 502.720308] RIP: 0010:trace_note.isra.0+0x86/0x360 [ 502.732872] Call Trace: [ 502.733193] __blk_add_trace.cold+0x137/0x1a3 [ 502.733734] blk_add_trace_rq+0x7b/0xd0 [ 502.734207] blk_add_trace_rq_issue+0x54/0xa0 [ 502.734755] blk_mq_start_request+0xde/0x1b0 [ 502.735287] scsi_queue_rq+0x528/0x1140 ... [ 502.742704] sg_new_write.isra.0+0x16e/0x3e0 [ 502.747501] sg_ioctl+0x466/0x1100 Reproduce method: ioctl(/dev/sda, BLKTRACESETUP, blk_user_trace_setup[buf_size=127]) ioctl(/dev/sda, BLKTRACESTART) ioctl(/dev/sdb, BLKTRACESETUP, blk_user_trace_setup[buf_size=127]) ioctl(/dev/sdb, BLKTRACESTART) echo 0 > /sys/block/sdb/trace/enable & // Add delay(mdelay/msleep) before kernel enters blk_trace_free() ioctl$SG_IO(/dev/sda, SG_IO, ...) // Enters trace_note_tsk() after blk_trace_free() returned // Use mdelay in rcu region rather than msleep(which may schedule out) Remove blk_trace from running_list before calling blk_trace_free() by sysfs if blk_trace is at Blktrace_running state.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00254 16th percentileScored 2026-11-07
Fix Fixed Linux (Linux): 4.4.286, 4.9.285, 4.14.249 +5

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux2.6.30 and later4.4.286, 4.9.285, 4.14.249, 4.19.209, 5.4.150, 5.10.70, 5.14.9, 5.15Patch availableCNA
  • Linux VendorLinux Affected 2.6.30 and later Fixed in 4.4.286, 4.9.285, 4.14.249, 4.19.209, 5.4.150, 5.10.70, 5.14.9, 5.15 Patch available CNA

CPE configurations NVD · 3

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*2.6.30 to before 4.4.286; 4.5 to before 4.9.285; 4.10 to before 4.14.249; 4.15 to before 4.19.209; 4.20 to before 5.4.150; 5.5 to before 5.10.70; 5.11 to before 5.14.9VulnerableLinux
cpe:2.3:o:linux:linux_kernel:5.15:rc1:*:*:*:*:*:*5.15 rc1VulnerableLinux
cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:*5.15 rc2VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 2.6.30 to before 4.4.286; 4.5 to before 4.9.285; 4.10 to before 4.14.249; 4.15 to before 4.19.209; 4.20 to before 5.4.150; 5.5 to before 5.10.70; 5.11 to before 5.14.9 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:5.15:rc1:*:*:*:*:*:* Versions 5.15 rc1 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:* Versions 5.15 rc2 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 4.4.286, 4.9.285, 4.14.249, 4.19.209, 5.4.150, 5.10.70, 5.14.9, 5.15

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Not affected: 4 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-47375
  2. 2026-10-03 Alias added: GHSA-x6vg-gvf6-hmp9

References

Patch 8

  • 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
See all 15278 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences