CyberSecBulletin
CVE-2026-64558NVD status: Analyzed

Linux: Heap-based Buffer Overflow

Published Updated By the CyberSecBulletin desk

CVE-2026-64558 is a high-severity heap-based buffer overflow 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 02028a24e26d85262ab9c8fc4344e1f3503007fc, 433e5e70cdc1edf382d28d08a885b22e2b98b7da, 614aa0491c7a190556c2345dddee0b6f5ed90989 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 0.12% 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 02028a24e26d85262ab9c8fc4344e1f3503007fc or 433e5e70cdc1edf382d28d08a885b22e2b98b7da or 614aa0491c7a190556c2345dddee0b6f5ed90989 or 1ac287e2af9a9112fe271427ef45eceb26bce8b4, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.12.97 or 6.18.40 or 7.1.5, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux8fcc231ce3bea12b78bb94b280cdc03cff342435 up to, but not including, 02028a24e26d85262ab9c8fc4344e1f3503007fc; 8fcc231ce3bea12b78bb94b280cdc03cff342435 up to, but not including, 433e5e70cdc1edf382d28d08a885b22e2b98b7da; 8fcc231ce3bea12b78bb94b280cdc03cff342435 up to, but not including, 614aa0491c7a190556c2345dddee0b6f5ed90989; 8fcc231ce3bea12b78bb94b280cdc03cff342435 up to, but not including, 1ac287e2af9a9112fe271427ef45eceb26bce8b4; 6.1202028a24e26d85262ab9c8fc4344e1f3503007fc, 433e5e70cdc1edf382d28d08a885b22e2b98b7da, 614aa0491c7a190556c2345dddee0b6f5ed90989, 1ac287e2af9a9112fe271427ef45eceb26bce8b4
LinuxLinux Kernel6.12 up to, but not including, 6.12.97; 6.13 up to, but not including, 6.18.40; 6.19 up to, but not including, 7.1.56.12.97, 6.18.40, 7.1.5

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/pkey: Check length in pkey_pckmo handler implementation Explicitly check the length of the target buffer in the pkey_pckmo implementation of the key_to_protkey() handler function. The handler function fails, if the generated output data exceeds the length of the provided target buffer.

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

The underlying weakness: Heap-based Buffer Overflow

The product writes past the end of a buffer that was allocated on the heap.

How developers prevent this class of flaw

  • Pre-design: Use a language or compiler that performs automatic bounds checking.
  • Use an abstraction library to abstract away risky APIs. Not a complete solution.
  • 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 Heap-based Buffer Overflow vulnerabilities (CWE-122)

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 Heap-based Buffer Overflow vulnerabilities

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