Improper input validation in Linux kernel - CVE-2026-53392

Vulnerability identifier: #VU138869

CSH Severity: Medium

CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-53392

CWE-ID: CWE-20

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper input validation in ff_layout_alloc_lseg() in the NFSv4 flexfiles layout handling when processing a malformed flexfiles layout body with a zero filehandle-version array count. A remote attacker can send a specially crafted flexfiles layout to cause a denial of service.

The issue can lead to a null pointer dereference and kernel panic.

Linux kernel
Debian Linux
Red Hat Enterprise Linux for Real Time
Red Hat Enterprise Linux for Real Time for NFV
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
Red Hat CodeReady Linux Builder for x86_64
Red Hat CodeReady Linux Builder for Power, little endian
Red Hat CodeReady Linux Builder for ARM 64
openEuler
kernel (Red Hat package)
kernel-rt (Red Hat package)
kernel
python3-perf-debuginfo
python3-perf
python2-perf-debuginfo
python2-perf
perf-debuginfo
perf
kernel-tools-devel
kernel-tools
kernel-source
kernel-devel
kernel-debugsource
kernel-debuginfo
bpftool-debuginfo
bpftool
kernel-tools-debuginfo
kernel-headers
linux (Debian package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel (Red Hat package) - addressed in versions 4.18.0-553.159.1.el8_10, 6.12.0-211.50.1.el10_2
kernel-rt (Red Hat package) - update to 4.18.0-553.159.1.rt7.500.el8_10
kernel - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-329.0.0.230
python3-perf-debuginfo - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-329.0.0.230
python3-perf - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-329.0.0.230
python2-perf-debuginfo - update to 4.19.90-2608.3.0.0385
python2-perf - update to 4.19.90-2608.3.0.0385
perf-debuginfo - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-329.0.0.230
perf - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-329.0.0.230
kernel-tools-devel - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-329.0.0.230
kernel-tools - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-329.0.0.230
kernel-source - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-329.0.0.230
kernel-devel - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-329.0.0.230
kernel-debugsource - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-329.0.0.230
kernel-debuginfo - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-329.0.0.230
bpftool-debuginfo - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-329.0.0.230
bpftool - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-329.0.0.230
kernel-tools-debuginfo - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-329.0.0.230
kernel-headers - update to 5.10.0-329.0.0.230
linux (Debian package) - update to 6.12.96-1

• https://git.kernel.org/stable/c/2131ed64b767ffa8bcdb3677d90f3964e39aabc8
• https://git.kernel.org/stable/c/2c6bb3c40bc24f6aa8dfbe6fe98c3ad6389203f2
• https://git.kernel.org/stable/c/7779c85028a0676fb190cde4f0c540f4f8e97761
• https://git.kernel.org/stable/c/d8c90c7cc061265d5f2813a1f5c82ef2f4707e67

• Improper input validation in Linux kernel nfs flexfilelayout
• Debian update for linux
• openEuler 20.03 LTS SP4 update for kernel
• openEuler 22.03 LTS SP4 update for kernel
• Red Hat Enterprise Linux 10 update for kernel
• Red Hat Enterprise Linux 8 update for kernel-rt
• Red Hat Enterprise Linux 8 update for kernel