CyberSecBulletin
CVE-2026-64368NVD status: Modified

Linux: Improper Initialization

Published Updated By the CyberSecBulletin desk

CVE-2026-64368 is a high-severity improper initialization vulnerability in Linux, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 6256899c3a34674bba6076884aedbba49fc695e4, 7e706d50fa119eead6376bf0ef973e8d73a96030, 2382971aaaef5bf85a651234c64906f59580b8be 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 0.42% 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 6256899c3a34674bba6076884aedbba49fc695e4 or 7e706d50fa119eead6376bf0ef973e8d73a96030 or 2382971aaaef5bf85a651234c64906f59580b8be or 0d18ccef142f04433dfb2a0c120cf223d2b8a42c, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.6.145 or 6.12.96 or 6.18.39 or 7.1.4, whichever matches your release line, or a later version.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux9ce67395f5a0cdec6ce152d26bfda13b98b25c01 up to, but not including, 6256899c3a34674bba6076884aedbba49fc695e4; 9ce67395f5a0cdec6ce152d26bfda13b98b25c01 up to, but not including, 7e706d50fa119eead6376bf0ef973e8d73a96030; 9ce67395f5a0cdec6ce152d26bfda13b98b25c01 up to, but not including, 2382971aaaef5bf85a651234c64906f59580b8be; 9ce67395f5a0cdec6ce152d26bfda13b98b25c01 up to, but not including, 0d18ccef142f04433dfb2a0c120cf223d2b8a42c; 9ce67395f5a0cdec6ce152d26bfda13b98b25c01 up to, but not including, 648927ceb84021a25a0fbd5673740956f318d534; 6.26256899c3a34674bba6076884aedbba49fc695e4, 7e706d50fa119eead6376bf0ef973e8d73a96030, 2382971aaaef5bf85a651234c64906f59580b8be, 0d18ccef142f04433dfb2a0c120cf223d2b8a42c, 648927ceb84021a25a0fbd5673740956f318d534
LinuxLinux Kernel6.2 up to, but not including, 6.6.145; 6.7 up to, but not including, 6.12.96; 6.13 up to, but not including, 6.18.39; 6.19 up to, but not including, 7.1.46.6.145, 6.12.96, 6.18.39, 7.1.4

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
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
HighSuccess depends on conditions outside the attacker's control.
Privileges required
NoneNo account or login is needed.
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:N/AC:H/PR:N/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: mm/slab: do not limit zeroing to orig_size when only red zoning is enabled When init (zeroing) on allocation is requested, for kmalloc() we generally have to zero the full object size even if a smaller size is requested, in order to provide krealloc()'s __GFP_ZERO guarantees. But if we track the requested size, krealloc() uses that information to do the right thing, so we can zero only the requested size. With red zoning also enabled, any extra size became part of the red zone, so it must not be zeroed and thus we must zero only the requested size. However the current check is imprecise, and will trigger also when only SLAB_RED_ZONE is enabled without SLAB_STORE_USER (which enables tracking the requested size). This means enabling red zoning alone can compromise krealloc()'s __GFP_ZERO contract. Fix this by using slub_debug_orig_size() instead, which is the exact check for whether the requested size is tracked. We don't need to care if red zoning is also enabled or not. Also update and expand the comment accordingly.

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

The underlying weakness: Improper Initialization

The product does not initialize or incorrectly initializes a resource.

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, in Java, if the programmer does not explicitly initialize a variable, then the code could produce a compile-time error (if the variable is local) or automatically initialize the variable to the default value for the variable's type. In Perl, if explicit initialization is not performed, then a default value of undef is assigned, which is interpreted as 0, false, or an equivalent value depending on the context in which the variable is accessed.
  • Identify all variables and data stores that receive information from external sources, and apply input validation to make sure that they are only initialized to expected values.
  • Explicitly initialize all your variables and other data stores, either during declaration or just before the first usage.

More Improper Initialization vulnerabilities (CWE-665)

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 Improper Initialization vulnerabilities

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