CVE-2026-64040 cachefiles: Fix error return when vfs_mkdir() fails

What is CVE-2026-64040?

CVE-2026-64040 is a medium-severity vulnerability in Linux kernel, published on 19 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

cachefiles: Fix error return when vfs_mkdir() fails

When vfs_mkdir() fails, the error code is not extracted from the returned error pointer. This causes mkdir_error to be reached with ret=0, which leads to returning ERR_PTR(0) (NULL) instead of a proper error pointer.

Fix this by extracting the error code from the error pointer when vfs_mkdir() fails.

Weakness: CWE-252

Which versions are affected by CVE-2026-64040?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-64040?

Apply the vendor's patch.

Is CVE-2026-64040 being exploited?

There is no known exploitation of CVE-2026-64040 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2026-64040, DEBIAN-CVE-2026-64040, GHSA-249r-xf46-wj4v, UBUNTU-CVE-2026-64040.