Linux KernelOperating system · Linux

CVE-2024-26685

MEDIUM · 5.5 CVSS v3.1 Published 2024-04-03
Fix available
A fix is available. Upgrade to 3.3 / 3.5 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: nilfs2: fix potential bug in end_buffer_async_write According to a syzbot report, end_buffer_async_write(), which handles the completion of block device writes, may detect abnormal condition of the buffer async_write flag and cause a BUG_ON failure when using nilfs2. Nilfs2 itself does not use end_buffer_async_write(). But, the async_write flag is now used as a marker by commit 7f42ec394156 ("nilfs2: fix issue with race condition of competition between segments for dirty blocks") as a means of resolving double list insertion of dirty blocks in nilfs_lookup_dirty_data_buffers() and nilfs_lookup_node_buffers() and the resulting crash. This modification is safe as long as it is used for file data and b-tree node blocks where the page caches are independent. However, it was irrelevant and redundant to also introduce async_write for segment summary and super root blocks that share buffers with the backing device. This led to the possibility that the BUG_ON check in end_buffer_async_write would fail as described above, if independent writebacks of the backing device occurred in parallel. The use of async_write for segment summary buffers has already been removed in a previous change. Fix this issue by removing the manipulation of the async_write flag for the remaining super root block buffer.

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-787

The program writes past the bounds of a buffer, overwriting adjacent memory an attacker can turn to their advantage. Crafted input can overwrite control data and redirect execution. Remediation is validating every index and length before a write, plus modern memory-safety mitigations.

General guidance for the out-of-bounds write 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:>= 3.2.52, < 3.3>= 3.4.83, < 3.5>= 3.10.16, < 3.11>= 3.11.5, < 4.19.307>= 4.20, < 5.4.269>= 5.5, < 5.10.210>= 5.11, < 5.15.149>= 5.16, < 6.1.79>= 6.2, < 6.6.18>= 6.7, < 6.7.6= 6.8
Debian LinuxOperating system
Affected:= 10.0

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 3.3 / 3.5 / 3.11 or later
Fixed in 3.33.53.11
Vendor patch git.kernel.org →
Recommended fix High confidence

Linux Kernel >= 4.19.307 (or 5.4.257+, 5.10.118+, 5.15.77+, 6.1.22+)

  1. Identify the running Linux kernel version using `uname -r` or `cat /proc/version`
  2. Check if the system uses nilfs2 filesystem by examining mount points with `mount | grep nilfs2`
  3. If using nilfs2, backup all critical data before kernel update as a precaution
  4. Upgrade the Linux kernel to version 4.19.307 or later, or to a version >= 5.4.257, >= 5.10.118, >= 5.15.77, or >= 6.1.22 which contain the fix
  5. For Debian 10 systems, upgrade to a newer Debian release (Debian 11 Bullseye or later) which includes a fixed kernel, or rebuild the kernel with the specific commit 2c3bdba00283a6c7a5b19481a59a730f46063803 applied
  6. Reboot the system into the updated kernel
  7. Verify the fix is applied by checking the kernel version and confirming nilfs2 functionality
Caveat Kernel upgrades may introduce compatibility changes; ensure dependent modules and drivers are compatible with the new version

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 $2,850. Get the upgrade done

Scan for this in your stack

Free · runs locally
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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-2024-26685 in production — separate from our analysis above.

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