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CVE-2024-53166· NVD / CVE Program· CNA Linux

block, bfq: fix bfqq uaf in bfq_limit_depth()

Noroxi assessment

Priority: Monitor (action score 31/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.25% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 01a853faaeaf3379ccf358ade582b1d28752126e, 906cdbdd3b018ff69cc830173bce277a847d4fdc, ada4ca5fd5a9d5212f28164d49a4885951c979c9; azl3 kernel 6.6.57.1-7 on Azure Linux 3.0 6.6.64.2-1; azl3 kernel 6.6.64.2-1 on Azure Linux 3.0 6.6.64.2-1.

Low priority for now. Upgrade to Linux Linux 01a853faaeaf3379ccf358ade582b1d28752126e, 906cdbdd3b018ff69cc830173bce277a847d4fdc, ada4ca5fd5a9d5212f28164d49a4885951c979c9; azl3 kernel 6.6.57.1-7 on Azure Linux 3.0 6.6.64.2-1; azl3 kernel 6.6.64.2-1 on Azure Linux 3.0 6.6.64.2-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

In the Linux kernel, the following vulnerability has been resolved: block, bfq: fix bfqq uaf in bfq_limit_depth() Set new allocated bfqq to bic or remove freed bfqq from bic are both protected by bfqd->lock, however bfq_limit_depth() is deferencing bfqq from bic without the lock, this can lead to UAF if the io_context is shared by multiple tasks. For example, test bfq with io_uring can trigger following UAF in v6.6: ================================================================== BUG: KASAN: slab-use-after-free in bfqq_group+0x15/0x50 Call Trace: <TASK> dump_stack_lvl+0x47/0x80 print_address_description.constprop.0+0x66/0x300 print_report+0x3e/0x70 kasan_report+0xb4/0xf0 bfqq_group+0x15/0x50 bfqq_request_over_limit+0x130/0x9a0 bfq_limit_depth+0x1b5/0x480 __blk_mq_alloc_requests+0x2b5/0xa00 blk_mq_get_new_requests+0x11d/0x1d0 blk_mq_submit_bio+0x286/0xb00 submit_bio_noacct_nocheck+0x331/0x400 __block_write_full_folio+0x3d0/0x640 writepage_cb+0x3b/0xc0 write_cache_pages+0x254/0x6c0 write_cache_pages+0x254/0x6c0 do_writepages+0x192/0x310 filemap_fdatawrite_wbc+0x95/0xc0 __filemap_fdatawrite_range+0x99/0xd0 filemap_write_and_wait_range.part.0+0x4d/0xa0 blkdev_read_iter+0xef/0x1e0 io_read+0x1b6/0x8a0 io_issue_sqe+0x87/0x300 io_wq_submit_work+0xeb/0x390 io_worker_handle_work+0x24d/0x550 io_wq_worker+0x27f/0x6c0 ret_from_fork_asm+0x1b/0x30 </TASK> Allocated by task 808602: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 __kasan_slab_alloc+0x83/0x90 kmem_cache_alloc_node+0x1b1/0x6d0 bfq_get_queue+0x138/0xfa0 bfq_get_bfqq_handle_split+0xe3/0x2c0 bfq_init_rq+0x196/0xbb0 bfq_insert_request.isra.0+0xb5/0x480 bfq_insert_requests+0x156/0x180 blk_mq_insert_request+0x15d/0x440 blk_mq_submit_bio+0x8a4/0xb00 submit_bio_noacct_nocheck+0x331/0x400 __blkdev_direct_IO_async+0x2dd/0x330 blkdev_write_iter+0x39a/0x450 io_write+0x22a/0x840 io_issue_sqe+0x87/0x300 io_wq_submit_work+0xeb/0x390 io_worker_handle_work+0x24d/0x550 io_wq_worker+0x27f/0x6c0 ret_from_fork+0x2d/0x50 ret_from_fork_asm+0x1b/0x30 Freed by task 808589: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 kasan_save_free_info+0x27/0x40 __kasan_slab_free+0x126/0x1b0 kmem_cache_free+0x10c/0x750 bfq_put_queue+0x2dd/0x770 __bfq_insert_request.isra.0+0x155/0x7a0 bfq_insert_request.isra.0+0x122/0x480 bfq_insert_requests+0x156/0x180 blk_mq_dispatch_plug_list+0x528/0x7e0 blk_mq_flush_plug_list.part.0+0xe5/0x590 __blk_flush_plug+0x3b/0x90 blk_finish_plug+0x40/0x60 do_writepages+0x19d/0x310 filemap_fdatawrite_wbc+0x95/0xc0 __filemap_fdatawrite_range+0x99/0xd0 filemap_write_and_wait_range.part.0+0x4d/0xa0 blkdev_read_iter+0xef/0x1e0 io_read+0x1b6/0x8a0 io_issue_sqe+0x87/0x300 io_wq_submit_work+0xeb/0x390 io_worker_handle_work+0x24d/0x550 io_wq_worker+0x27f/0x6c0 ret_from_fork+0x2d/0x50 ret_from_fork_asm+0x1b/0x30 Fix the problem by protecting bic_to_bfqq() with bfqd->lock.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Dec 27, 2024
Updated
Aug 5, 2026
EPSS
0.3% · 16th percentile

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
7.8
CNA · Linux
7.8
agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.17 and later · before 6.6.64
  • linux linux kernel6.7 and later · before 6.11.11
  • linux linux kernel6.12 and later · before 6.12.2

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.17affected
    • 76f1df88bbc2f984eb0418cc90de0a8384e63604 and later · before ada4ca5fd5a9d5212f28164d49a4885951c979c9affected · git
    • 76f1df88bbc2f984eb0418cc90de0a8384e63604 and later · before 906cdbdd3b018ff69cc830173bce277a847d4fdcaffected · git
    • 76f1df88bbc2f984eb0418cc90de0a8384e63604 and later · before dcaa738afde55085ac6056252e319479cf23cde2affected · git
    • 76f1df88bbc2f984eb0418cc90de0a8384e63604 and later · before 01a853faaeaf3379ccf358ade582b1d28752126eaffected · git
    • 76f1df88bbc2f984eb0418cc90de0a8384e63604 and later · before e8b8344de3980709080d86c157d24e7de07d70adaffected · git
    • before 5.17not affected · semver
    • 6.1.130 and later · up to and including 6.1.*not affected · semver
    • 6.6.64 and later · up to and including 6.6.*not affected · semver
    • 6.11.11 and later · up to and including 6.11.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.133-16.1.133-1
Debian:13linuxbefore 6.12.3-16.12.3-1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSkernel-64kbbefore 5.14.21-150400.24.150.15.14.21-150400.24.150.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSkernel-docsbefore 5.14.21-150400.24.150.15.14.21-150400.24.150.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSkernel-obs-buildbefore 5.14.21-150400.24.150.15.14.21-150400.24.150.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSkernel-sourcebefore 5.14.21-150400.24.150.15.14.21-150400.24.150.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSkernel-symsbefore 5.14.21-150400.24.150.15.14.21-150400.24.150.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_27before 18-150400.2.118-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_28before 15-150400.2.115-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_29before 13-150400.2.113-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_31before 11-150400.2.111-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_32before 11-150400.2.111-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_33before 10-150400.2.110-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_35before 8-150400.2.18-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_36before 1-150400.9.3.11-150400.9.3.1
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5_Update_15before 18-150500.2.118-150500.2.1
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5_Update_17before 13-150500.2.113-150500.2.1
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5_Update_21before 7-150500.2.17-150500.2.1
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5_Update_22before 7-150500.2.17-150500.2.1
SUSE:Linux Enterprise Live Patching 15 SP6kernel-livepatch-SLE15-SP6_Update_0before 19-150600.4.49.119-150600.4.49.1
SUSE:Linux Enterprise Live Patching 15 SP6kernel-livepatch-SLE15-SP6_Update_4before 13-150600.2.113-150600.2.1
SUSE:Linux Enterprise Live Patching 15 SP6kernel-livepatch-SLE15-SP6_Update_6before 8-150600.2.18-150600.2.1
SUSE:Linux Enterprise Live Patching 15 SP6kernel-livepatch-SLE15-SP6-RT_Update_0before 18-150600.3.118-150600.3.1
SUSE:Linux Enterprise Live Patching 15 SP6kernel-livepatch-SLE15-SP6-RT_Update_1before 17-150600.2.117-150600.2.1

+16

Same product

linux: all records

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Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux01a853faaeaf3379ccf358ade582b1d28752126eVendor (CNA)
Linux Linux906cdbdd3b018ff69cc830173bce277a847d4fdcVendor (CNA)
Linux Linuxada4ca5fd5a9d5212f28164d49a4885951c979c9Vendor (CNA)
Linux Linuxdcaa738afde55085ac6056252e319479cf23cde2Vendor (CNA)
Linux Linuxe8b8344de3980709080d86c157d24e7de07d70adVendor (CNA)
azl3 kernel 6.6.57.1-7 on Azure Linux 3.06.6.64.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 kernel 6.6.64.2-1 on Azure Linux 3.06.6.64.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.133-1 · Debian:12Package registry (OSV)
suse:kernel-livepatch-SLE15-SP4_Update_2913-150400.2.1 · SUSE:Linux Enterprise Live Patching 15 SP4Package registry (OSV)
suse:kernel-livepatch-SLE15-SP4_Update_3211-150400.2.1 · SUSE:Linux Enterprise Live Patching 15 SP4Package registry (OSV)
suse:kernel-livepatch-SLE15-SP4_Update_3310-150400.2.1 · SUSE:Linux Enterprise Live Patching 15 SP4Package registry (OSV)
suse:kernel-livepatch-SLE15-SP5_Update_1518-150500.2.1 · SUSE:Linux Enterprise Live Patching 15 SP5Package registry (OSV)
suse:kernel-livepatch-SLE15-SP5_Update_217-150500.2.1 · SUSE:Linux Enterprise Live Patching 15 SP5Package registry (OSV)
suse:kernel-livepatch-SLE15-SP6-RT_Update_018-150600.3.1 · SUSE:Linux Enterprise Live Patching 15 SP6Package registry (OSV)
suse:kernel-livepatch-SLE15-SP6-RT_Update_117-150600.2.1 · SUSE:Linux Enterprise Live Patching 15 SP6Package registry (OSV)
suse:kernel-livepatch-SLE15-SP6-RT_Update_213-150600.2.1 · SUSE:Linux Enterprise Live Patching 15 SP6Package registry (OSV)
suse:kernel-livepatch-SLE15-SP6-RT_Update_313-150600.2.1 · SUSE:Linux Enterprise Live Patching 15 SP6Package registry (OSV)
suse:kernel-livepatch-SLE15-SP6-RT_Update_412-150600.2.1 · SUSE:Linux Enterprise Live Patching 15 SP6Package registry (OSV)
suse:kernel-livepatch-SLE15-SP6-RT_Update_511-150600.2.1 · SUSE:Linux Enterprise Live Patching 15 SP6Package registry (OSV)
suse:kernel-livepatch-SLE15-SP6-RT_Update_68-150600.2.1 · SUSE:Linux Enterprise Live Patching 15 SP6Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

c
free(dev->buf);/* ... another thread is still running ... */process(dev->buf);

Fixed

c
lock(&dev->lock);free(dev->buf);dev->buf = NULL;unlock(&dev->lock);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records