CVE-2026-64596 is a vulnerability in Linux Kernel
Published on August 6, 2026
libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo()
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 assertion
enforces. No in-tree caller maps these executable.
Reproduce on CONFIG_DEBUG_VFS=y:
make -C tools/testing/selftests/dmabuf-heaps
sudo ./tools/testing/selftests/dmabuf-heaps/dmabuf-heap -t system
Products Associated with CVE-2026-64596
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Affected Versions
Linux:- Version 1e7ab6f67824343ee3e96f100f0937c393749a8a and below b9d45d328fcda4f0d3d281b7d6f12d3f181d9381 is affected.
- Version 1e7ab6f67824343ee3e96f100f0937c393749a8a and below 8e931557b317f0fb414839fa51fae1d5feb0ad97 is affected.
- Version 1e7ab6f67824343ee3e96f100f0937c393749a8a and below 6de2aeffabaafaeda819e60ec8d04f199711e11a is affected.
- Version 9b8076a9404568d6cb6673b9a079558b15051966 is affected.
- Version 6.15.6 and below 6.16 is affected.
- Version 6.16 is affected.
- Before 6.16 is unaffected.
- Version 6.18.39, <= 6.18.* is unaffected.
- Version 7.1.4, <= 7.1.* is unaffected.
- Version 7.2-rc1, <= * is unaffected.