CyberSecBulletin
CVE-2026-46281NVD status: Analyzed

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2026-46281 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 e9b057a44deff4c59c13f44672a5cc74dcd57522, b281adf71f786c325eb6d6d1582d4d05313438a8, 82d1f01292d3f09bf063f829f8ab8de12b4280a1 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 0.14% 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 e9b057a44deff4c59c13f44672a5cc74dcd57522 or b281adf71f786c325eb6d6d1582d4d05313438a8 or 82d1f01292d3f09bf063f829f8ab8de12b4280a1, 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
LinuxLinux4c5d3365882dbbc0784688784904f440d7a4c0f1 up to, but not including, e9b057a44deff4c59c13f44672a5cc74dcd57522; 4c5d3365882dbbc0784688784904f440d7a4c0f1 up to, but not including, b281adf71f786c325eb6d6d1582d4d05313438a8; 4c5d3365882dbbc0784688784904f440d7a4c0f1 up to, but not including, 82d1f01292d3f09bf063f829f8ab8de12b4280a1; 6.18e9b057a44deff4c59c13f44672a5cc74dcd57522, b281adf71f786c325eb6d6d1582d4d05313438a8, 82d1f01292d3f09bf063f829f8ab8de12b4280a1
LinuxLinux Kernel6.18 up to, but not including, 6.18.27; 6.19 up to, but not including, 7.0.4; 7.16.18.27, 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: vmalloc: fix buffer overflow in vrealloc_node_align() Commit 4c5d3365882d ("mm/vmalloc: allow to set node and align in vrealloc") added the ability to force a new allocation if the current pointer is on the wrong NUMA node, or if an alignment constraint is not met, even if the user is shrinking the allocation. On this path (need_realloc), the code allocates a new object of 'size' bytes and then memcpy()s 'old_size' bytes into it. If the request is to shrink the object (size < old_size), this results in an out-of-bounds write on the new buffer. Fix this by bounding the copy length by the new allocation size.

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. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Write vulnerabilities

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