CyberSecBulletin
CVE-2026-63824NVD status: Analyzed

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2026-63824 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 622ec2dcd59f21623f2a7ab773c80ceb7d555e3a, b1e247338bc71826a2d2def3e0874c34749df69a, 0f3058d7d26f81df9b68a18ddbe164bdc3c5eff3 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 0.17% 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 622ec2dcd59f21623f2a7ab773c80ceb7d555e3a or b1e247338bc71826a2d2def3e0874c34749df69a or 0f3058d7d26f81df9b68a18ddbe164bdc3c5eff3 or 5966e4e2ba213ab7ad559166152eb4f1f170dd2c, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.260 or 5.15.211 or 6.1.177 or 6.6.144, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux00d60fd3b93219ea854220f0fd264b86398cbc53 up to, but not including, 622ec2dcd59f21623f2a7ab773c80ceb7d555e3a; 00d60fd3b93219ea854220f0fd264b86398cbc53 up to, but not including, b1e247338bc71826a2d2def3e0874c34749df69a; 00d60fd3b93219ea854220f0fd264b86398cbc53 up to, but not including, 0f3058d7d26f81df9b68a18ddbe164bdc3c5eff3; 00d60fd3b93219ea854220f0fd264b86398cbc53 up to, but not including, 5966e4e2ba213ab7ad559166152eb4f1f170dd2c; 00d60fd3b93219ea854220f0fd264b86398cbc53 up to, but not including, 5165f1cc727f1322456735df212d8e26ec237a8d; 00d60fd3b93219ea854220f0fd264b86398cbc53 up to, but not including, b11c1fa32667692a2c0566e10163758e786e430c; 00d60fd3b93219ea854220f0fd264b86398cbc53 up to, but not including, 670fc6a311ed321522b7fff92cf0fc376b4f6e78; 00d60fd3b93219ea854220f0fd264b86398cbc53 up to, but not including, cb481e59ea6cae3b7796ac1d7a22b6b24c3f3c0b; and 1 more ranges622ec2dcd59f21623f2a7ab773c80ceb7d555e3a, b1e247338bc71826a2d2def3e0874c34749df69a, 0f3058d7d26f81df9b68a18ddbe164bdc3c5eff3, 5966e4e2ba213ab7ad559166152eb4f1f170dd2c, 5165f1cc727f1322456735df212d8e26ec237a8d, b11c1fa32667692a2c0566e10163758e786e430c
LinuxLinux Kernel4.20 up to, but not including, 5.10.260; 5.11 up to, but not including, 5.15.211; 5.16 up to, but not including, 6.1.177; 6.2 up to, but not including, 6.6.144; 6.7 up to, but not including, 6.12.95; 6.13 up to, but not including, 6.18.38; 6.19 up to, but not including, 7.1.35.10.260, 5.15.211, 6.1.177, 6.6.144, 6.12.95, 6.18.38

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 CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: KEYS: fix overflow in keyctl_pkey_params_get_2() The length for the internal output buffer is calculated incorrectly, which can result overflow when a too small buffer is provided. Fix the bug by allocating internal output with the size of the maximum length of the cryptographic primitive instead of caller provided 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. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Write vulnerabilities

Spotted an error? Tell us.