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

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-27 · updated 2026-06-25

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.

Affected products

Linux kernel: from 6.17 before 6.18.27; from 6.19 before 7.0.4 — fixed in 6.18.27, 7.0.4

How to fix

Upgrade to a fixed version: Linux kernel 6.18.27, 7.0.4. Check the vendor advisory for mitigations.

References

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