CVE-2026-46100 fs: afs: revert mmap_prepare() change

What is CVE-2026-46100?

CVE-2026-46100 is a high-severity vulnerability in Linux kernel, published on 27 May 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:

fs: afs: revert mmap_prepare() change

Partially reverts commit 9d5403b1036c ("fs: convert most other generic_file_*mmap() users to .mmap_prepare()").

This is because the .mmap invocation establishes a refcount, but .mmap_prepare is called at a point where a merge or an allocation failure might happen after the call, which would leak the refcount increment.

Functionality is being added to permit the use of .mmap_prepare in this case, but in the interim, we need to fix this.

Which versions are affected by CVE-2026-46100?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-46100?

Apply the vendor's patch.

Is CVE-2026-46100 being exploited?

There is no known exploitation of CVE-2026-46100 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-2026-46100, DEBIAN-CVE-2026-46100, GHSA-fff5-56xf-g7v8, UBUNTU-CVE-2026-46100.