Improper Initialization in Linux kernel - CVE-2026-64368

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Main Vulnerability Database Vulnerabilities #VU139603

Improper Initialization in Linux kernel - CVE-2026-64368

Published: July 27, 2026


Vulnerability identifier: #VU139603
CSH Severity: Low
CVSS v4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-64368
CWE-ID: CWE-665
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to disclose sensitive information.

The vulnerability exists due to improper initialization in slab allocation handling in mm/slub.c when allocating kmalloc objects with zeroing enabled. A local user can trigger a memory allocation pattern that leaves part of the allocated object uninitialized to disclose sensitive information.

The issue occurs when requested-size tracking is not enabled while red zoning alone is enabled, which can break krealloc() __GFP_ZERO expectations.


Affected software

Linux kernel
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
Ubuntu
kernel (Red Hat package)
linux (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)

How to mitigate CVE-2026-64368

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel (Red Hat package) - addressed in versions 5.14.0-687.38.1.el9_8, 6.12.0-211.46.1.el10_2
linux (Ubuntu package) - addressed in versions 7.0.0-31.31, 7.0.0-31.31.1, 7.0.0-31.31~24.04.1, 7.0.0-1006.7, 7.0.0-1011.11~24.04.1, 7.0.0-1012.12, 7.0.0-1012.12~24.04.1
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1013.13

External References

Related Security Bulletins