CyberSecBulletin
CVE-2026-72066NVD status: Received

Linux: Buffer Copy without Checking Size of Input

Published Updated By the CyberSecBulletin desk

CVE-2026-72066 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 27481cf4365a6ff5c9be3590143e7ed434000266, 2408be459c70ef4250da1a9e50f5478e6b250d61, de4d3d8ae17dc8b4cf8c59436c4b7e2dc2491635 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 0.18% 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 27481cf4365a6ff5c9be3590143e7ed434000266 or 2408be459c70ef4250da1a9e50f5478e6b250d61 or de4d3d8ae17dc8b4cf8c59436c4b7e2dc2491635 or 998f66e9ce320f3433f60b948e3698b744754a46, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux98f8cdce1db580b99fce823a48eea2cb2bdb261e up to, but not including, 27481cf4365a6ff5c9be3590143e7ed434000266; 98f8cdce1db580b99fce823a48eea2cb2bdb261e up to, but not including, 2408be459c70ef4250da1a9e50f5478e6b250d61; 98f8cdce1db580b99fce823a48eea2cb2bdb261e up to, but not including, de4d3d8ae17dc8b4cf8c59436c4b7e2dc2491635; 98f8cdce1db580b99fce823a48eea2cb2bdb261e up to, but not including, 998f66e9ce320f3433f60b948e3698b744754a46; 98f8cdce1db580b99fce823a48eea2cb2bdb261e up to, but not including, 61a73a123ac7a7fbc57382531f8cb7092d569aba; 98f8cdce1db580b99fce823a48eea2cb2bdb261e up to, but not including, 6cb15b81ff545840048fb0e1a6e827d560dbf367; 98f8cdce1db580b99fce823a48eea2cb2bdb261e up to, but not including, 631d53102da9f469c96b882b770336bec095b833; 98f8cdce1db580b99fce823a48eea2cb2bdb261e up to, but not including, 86f436567f2516a0083b210bedc933544826a2c3; and 1 more ranges27481cf4365a6ff5c9be3590143e7ed434000266, 2408be459c70ef4250da1a9e50f5478e6b250d61, de4d3d8ae17dc8b4cf8c59436c4b7e2dc2491635, 998f66e9ce320f3433f60b948e3698b744754a46, 61a73a123ac7a7fbc57382531f8cb7092d569aba, 6cb15b81ff545840048fb0e1a6e827d560dbf367

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: cpu: hotplug: Bound hotplug states sysfs output states_show() adds CPU hotplug state names into a single sysfs buffer using sprintf(). With enough registered states, this can write past the end of the PAGE_SIZE buffer. Use sysfs_emit_at() so output is bounded.

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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