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Linux KernelOperating system · Linux

CVE-2026-46061

MEDIUM · 5.5 CVSS v3.1 Published 2026-05-27
Fix available
A fix is available. Upgrade to 6.12.86 / 6.15 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: jbd2: fix deadlock in jbd2_journal_cancel_revoke() Commit f76d4c28a46a ("fs/jbd2: use sleeping version of __find_get_block()") changed jbd2_journal_cancel_revoke() to use __find_get_block_nonatomic() which holds the folio lock instead of i_private_lock. This breaks the lock ordering (folio -> buffer) and causes an ABBA deadlock when the filesystem blocksize < pagesize: T1 T2 ext4_mkdir() ext4_init_new_dir() ext4_append() ext4_getblk() lock_buffer() <- A sync_blockdev() blkdev_writepages() writeback_iter() writeback_get_folio() folio_lock() <- B ext4_journal_get_create_access() jbd2_journal_cancel_revoke() __find_get_block_nonatomic() folio_lock() <- B block_write_full_folio() lock_buffer() <- A This can occasionally cause generic/013 to hang. Fix by only calling __find_get_block_nonatomic() when the passed buffer_head doesn't belong to the bdev, which is the only case that we need to look up its bdev alias. Otherwise, the lookup is redundant since the found buffer_head is equal to the one we passed in.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-667

Shared resources are accessed without correct locking, so concurrent operations interleave into inconsistent — and sometimes exploitable — states, or deadlock the service outright. These bugs are subtle and timing-dependent. The fix is correct, consistent locking or atomic operations around every shared resource.

General guidance for the improper locking class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 6.12.31, < 6.12.86>= 6.14.9, < 6.15>= 6.15.1, < 6.18.27>= 6.19, < 7.0.4= 6.15

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 6.12.86 / 6.15 / 6.18.27 or later
Fixed in 6.12.866.156.18.27
Vendor patch git.kernel.org →
Recommended fix High confidence

Linux kernel 6.12.86, 6.15, 6.18.27, or 7.0.4 (depending on your stable branch)

  1. Identify the currently running Linux kernel version using 'uname -r'
  2. Determine which affected version range your kernel falls into (6.12.31-6.12.85, 6.14.9-6.14.x, 6.15.1-6.18.26, or 6.19-7.0.3)
  3. Upgrade to a fixed kernel version: 6.12.86 or later, 6.15 (if available), 6.18.27 or later, or 7.0.4 or later
  4. Reboot the system to load the new kernel
  5. Verify the fix is applied by checking the kernel version matches a fixed release
Caveat Kernel upgrades are generally safe but may require rebuilding third-party kernel modules; ensure compatible drivers are available before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,600. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-46061 in production — separate from our analysis above.

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What this is

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  • Version or environment caveats, and links to real fixes
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