CyberSecBulletin
CVE-2026-46045NVD status: Analyzed

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2026-46045 is a high-severity out-of-bounds write vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 98623c7e2a51eab1833c8628d33fa9c6ef3ce325, 3115fa2f62970d98f2a639145fb8e2767db8bbf9, 7701e68b5072faa03a8f30b4081dc16df9092381 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.13% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 98623c7e2a51eab1833c8628d33fa9c6ef3ce325 or 3115fa2f62970d98f2a639145fb8e2767db8bbf9 or 7701e68b5072faa03a8f30b4081dc16df9092381, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.18.27 or 7.0.4, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux5ab829f1971dc99f2aac10846c378e67fc875abc up to, but not including, 98623c7e2a51eab1833c8628d33fa9c6ef3ce325; 5ab829f1971dc99f2aac10846c378e67fc875abc up to, but not including, 3115fa2f62970d98f2a639145fb8e2767db8bbf9; 5ab829f1971dc99f2aac10846c378e67fc875abc up to, but not including, 7701e68b5072faa03a8f30b4081dc16df9092381; 6.1898623c7e2a51eab1833c8628d33fa9c6ef3ce325, 3115fa2f62970d98f2a639145fb8e2767db8bbf9, 7701e68b5072faa03a8f30b4081dc16df9092381
LinuxLinux Kernel6.18 up to, but not including, 6.18.27; 6.19 up to, but not including, 7.0.46.18.27, 7.0.4

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Official description

In the Linux kernel, the following vulnerability has been resolved: md/md-llbitmap: skip reading rdevs that are not in_sync When reading bitmap pages from member disks, the code iterates through all rdevs and attempts to read from the first available one. However, it only checks for raid_disk assignment and Faulty flag, missing the In_sync flag check. This can cause bitmap data to be read from spare disks that are still being rebuilt and don't have valid bitmap information yet. Reading stale or uninitialized bitmap data from such disks can lead to incorrect dirty bit tracking, potentially causing data corruption during recovery or normal operation. Add the In_sync flag check to ensure bitmap pages are only read from fully synchronized member disks that have valid bitmap data.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Write

The product writes data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Out-of-bounds Write vulnerabilities (CWE-787)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Write vulnerabilities

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