CyberSecBulletin
CVE-2026-68451NVD status: Received

Linux: Buffer Copy without Checking Size of Input

Published Updated By the CyberSecBulletin desk

CVE-2026-68451 is a high-severity buffer copy without checking size of input 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 7dc306ff7c4d951582adaae65e0aee9fb4968dbe, 447a37a6bef11bfd3645069e380460b11386e2b9, f0831f13c42c1261d449dcee8a035e1c6cd9fcaa 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 7dc306ff7c4d951582adaae65e0aee9fb4968dbe or 447a37a6bef11bfd3645069e380460b11386e2b9 or f0831f13c42c1261d449dcee8a035e1c6cd9fcaa or dd25bd9b0f36849808bd7625dcc59dd4c1aeef3e, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxfa6999e326fe7851ecbd572b8cb9be8e930ebf41 up to, but not including, 7dc306ff7c4d951582adaae65e0aee9fb4968dbe; fa6999e326fe7851ecbd572b8cb9be8e930ebf41 up to, but not including, 447a37a6bef11bfd3645069e380460b11386e2b9; fa6999e326fe7851ecbd572b8cb9be8e930ebf41 up to, but not including, f0831f13c42c1261d449dcee8a035e1c6cd9fcaa; fa6999e326fe7851ecbd572b8cb9be8e930ebf41 up to, but not including, dd25bd9b0f36849808bd7625dcc59dd4c1aeef3e; fa6999e326fe7851ecbd572b8cb9be8e930ebf41 up to, but not including, ecc3b8691c1935f9f3e4eb964ab11e40fdec17f5; fa6999e326fe7851ecbd572b8cb9be8e930ebf41 up to, but not including, 013a4484f061a2b41f052e25c0015203287e63f1; fa6999e326fe7851ecbd572b8cb9be8e930ebf41 up to, but not including, 8fa3e9435a13c335efb63fb4f4e77531a0031159; fa6999e326fe7851ecbd572b8cb9be8e930ebf41 up to, but not including, a9ae0f6dd45c3ccc1d69363f7aea8af179122730; and 1 more ranges7dc306ff7c4d951582adaae65e0aee9fb4968dbe, 447a37a6bef11bfd3645069e380460b11386e2b9, f0831f13c42c1261d449dcee8a035e1c6cd9fcaa, dd25bd9b0f36849808bd7625dcc59dd4c1aeef3e, ecc3b8691c1935f9f3e4eb964ab11e40fdec17f5, 013a4484f061a2b41f052e25c0015203287e63f1

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: s390/zcrypt: Validate length for CCA ECC private key requests cca_ecc2protkey() derives the copy length for the CPRB parameter block directly from the length field in the key token. Reject the request early if the token length exceeds the available space in the parameter block.

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

The underlying weakness: Buffer Copy without Checking Size of Input

The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output 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 Buffer Copy without Checking Size of Input vulnerabilities (CWE-120)

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 Buffer Copy without Checking Size of Input vulnerabilities

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