CVE-2026-64596

Technical Description

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

libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo()

Since commit 1e7ab6f67824 ("anon_inode: rework assertions"),

path_noexec() warns when an anonymous-inode file is mmap'd from a

superblock that has not set SB_I_NOEXEC. dma-buf backs its files this

way and never set the flag, so mmap of any exported buffer trips the

warning on a CONFIG_DEBUG_VFS=y kernel:

WARNING: CPU: 11 PID: 121813 at fs/exec.c:118 path_noexec+0x47/0x50

do_mmap+0x2b5/0x680

vm_mmap_pgoff+0x129/0x210

ksys_mmap_pgoff+0x177/0x240

__x64_sys_mmap+0x33/0x70

init_pseudo() sets up internal SB_NOUSER mounts that are never

path-reachable. Set both flags here so every pseudo filesystem gets

them by default instead of each caller setting them.

SB_I_NODEV is inert for unreachable mounts. SB_I_NOEXEC has one

visible effect: an executable mapping of a pseudo-fs fd, such as a

dma-buf, now fails with -EPERM, which is the invariant the

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