CVE-2026-31654

/// Technical description

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

mm/vma: fix memory leak in __mmap_region()

commit 605f6586ecf7 ("mm/vma: do not leak memory when .mmap_prepare

swaps the file") handled the success path by skipping get_file() via

file_doesnt_need_get, but missed the error path.

When /dev/zero is mmap'd with MAP_SHARED, mmap_zero_prepare() calls

shmem_zero_setup_desc() which allocates a new shmem file to back the

mapping. If __mmap_new_vma() subsequently fails, this replacement

file is never fput()'d - the original is released by

ksys_mmap_pgoff(), but nobody releases the new one.

Add fput() for the swapped file in the error path.

Reproducible with fault injection.

FAULT_INJECTION: forcing a failure.

name failslab, interval 1, probability 0, space 0, times 1

CPU: 2 UID: 0 PID: 366 Comm: syz.7.14 Not tainted 7.0.0-rc6 #2 PREEMPT(full)

Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014

Call Trace:

<T

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References