Linux KernelOperating system · Linux
CVE-2026-45985
A fix is available.
Upgrade to 5.10.253 / 5.15.203 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 · uneditedIn the Linux kernel, the following vulnerability has been resolved: ext4: don't set EXT4_GET_BLOCKS_CONVERT when splitting before submitting I/O When allocating blocks during within-EOF DIO and writeback with dioread_nolock enabled, EXT4_GET_BLOCKS_PRE_IO was set to split an existing large unwritten extent. However, EXT4_GET_BLOCKS_CONVERT was set when calling ext4_split_convert_extents(), which may potentially result in stale data issues. Assume we have an unwritten extent, and then DIO writes the second half. [UUUUUUUUUUUUUUUU] on-disk extent U: unwritten extent [UUUUUUUUUUUUUUUU] extent status tree |<- ->| ----> dio write this range First, ext4_iomap_alloc() call ext4_map_blocks() with EXT4_GET_BLOCKS_PRE_IO, EXT4_GET_BLOCKS_UNWRIT_EXT and EXT4_GET_BLOCKS_CREATE flags set. ext4_map_blocks() find this extent and call ext4_split_convert_extents() with EXT4_GET_BLOCKS_CONVERT and the above flags set. Then, ext4_split_convert_extents() calls ext4_split_extent() with EXT4_EXT_MAY_ZEROOUT, EXT4_EXT_MARK_UNWRIT2 and EXT4_EXT_DATA_VALID2 flags set, and it calls ext4_split_extent_at() to split the second half with EXT4_EXT_DATA_VALID2, EXT4_EXT_MARK_UNWRIT1, EXT4_EXT_MAY_ZEROOUT and EXT4_EXT_MARK_UNWRIT2 flags set. However, ext4_split_extent_at() failed to insert extent since a temporary lack -ENOSPC. It zeroes out the first half but convert the entire on-disk extent to written since the EXT4_EXT_DATA_VALID2 flag set, but left the second half as unwritten in the extent status tree. [0000000000SSSSSS] data S: stale data, 0: zeroed [WWWWWWWWWWWWWWWW] on-disk extent W: written extent [WWWWWWWWWWUUUUUU] extent status tree Finally, if the DIO failed to write data to the disk, the stale data in the second half will be exposed once the cached extent entry is gone. Fix this issue by not passing EXT4_GET_BLOCKS_CONVERT when splitting an unwritten extent before submitting I/O, and make ext4_split_convert_extents() to zero out the entire extent range to zero for this case, and also mark the extent in the extent status tree for consistency.
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 analysisA detailed technical summary for this CVE is being prepared.
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:
>= 3.15, < 5.10.253>= 5.11, < 5.15.203>= 5.16, < 6.6.130>= 6.7, < 6.12.77>= 6.13, < 6.18.17>= 6.19, < 6.19.4CVSS 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 5.10.253 / 5.15.203 / 6.6.130 or later
Fixed in
5.10.2535.15.2036.6.130
Vendor patch
git.kernel.org →
Recommended fix
High confidence
6.12.77 (or latest 6.12.x stable, or equivalent in other supported branches: 5.10.253+, 5.15.203+, 6.6.130+)
- 1. Identify the current running Linux kernel version using 'uname -r'
- 2. Check if the kernel version falls within any of the affected ranges: >= 3.15 and < 5.10.253, >= 5.11 and < 5.15.203, >= 5.16 and < 6.6.130, or >= 6.7 and < 6.12.77
- 3. If affected, schedule a maintenance window for kernel upgrade
- 4. Upgrade the Linux kernel to a fixed version: 5.10.253 or later, 5.15.203 or later, 6.6.130 or later, or 6.12.77 or later
- 5. For production systems, prefer the latest stable release in your chosen branch (e.g., 6.12.x series)
- 6. After reboot, verify the fix is applied by checking the kernel version and confirming ext4 filesystem is functioning correctly
Caveat Kernel upgrades may require system reboot and could have compatibility implications with proprietary kernel modules or specific hardware drivers; test thoroughly in non-production environment first
Generated from the published advisory — verify against the referenced sources before acting.
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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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-45985 in production — separate from our analysis above.
Know something about CVE-2026-45985?
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- A config change or rule that shut the vector down
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