Improper input validation in Linux kernel - CVE-2026-64379

Vulnerability identifier: #VU139583

CSH Severity: Medium

CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-64379

CWE-ID: CWE-20

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to modify file mode bits.

The vulnerability exists due to improper input validation in parse_dacl() when processing a server-provided NFS mode SID. A remote attacker can provide crafted mode values to modify file mode bits.

The issue occurs when modefromsid is active.

Linux kernel
Red Hat Enterprise Linux for Real Time
Red Hat Enterprise Linux for Real Time for NFV
Anolis OS
openEuler
Ubuntu
kernel-rt (Red Hat package)
kernel-devel
kernel-debug-core
kernel-debug
kernel-cross-headers
kernel-core
kernel
bpftool
kernel-debug-devel
kernel-debug-modules
kernel-debug-modules-extra
kernel-headers
kernel-modules
kernel-modules-extra
kernel-tools
kernel-tools-libs
kernel-tools-libs-devel
perf
python3-perf
kernel-abi-stablelists
kernel-doc
python3-perf-debuginfo
bpftool-debuginfo
kernel-debuginfo
kernel-debugsource
kernel-source
kernel-tools-debuginfo
kernel-tools-devel
perf-debuginfo
kernel-extra-modules
linux (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel-rt (Red Hat package) - update to 4.18.0-553.157.1.rt7.498.el8_10
kernel-devel - update to 4.18.0-553.157.1.0.1
kernel-debug-core - update to 4.18.0-553.157.1.0.1
kernel-debug - update to 4.18.0-553.157.1.0.1
kernel-cross-headers - update to 4.18.0-553.157.1.0.1
kernel-core - update to 4.18.0-553.157.1.0.1
kernel - update to 4.18.0-553.157.1.0.1
bpftool - update to 4.18.0-553.157.1.0.1
kernel-debug-devel - update to 4.18.0-553.157.1.0.1
kernel-debug-modules - update to 4.18.0-553.157.1.0.1
kernel-debug-modules-extra - update to 4.18.0-553.157.1.0.1
kernel-headers - update to 4.18.0-553.157.1.0.1
kernel-modules - update to 4.18.0-553.157.1.0.1
kernel-modules-extra - update to 4.18.0-553.157.1.0.1
kernel-tools - update to 4.18.0-553.157.1.0.1
kernel-tools-libs - update to 4.18.0-553.157.1.0.1
kernel-tools-libs-devel - update to 4.18.0-553.157.1.0.1
perf - update to 4.18.0-553.157.1.0.1
python3-perf - update to 4.18.0-553.157.1.0.1
kernel-abi-stablelists - update to 4.18.0-553.157.1.0.1
kernel-doc - update to 4.18.0-553.157.1.0.1
bpftool - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
python3-perf - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
python3-perf-debuginfo - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
bpftool-debuginfo - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-debuginfo - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-debugsource - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-devel - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-headers - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-source - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-tools - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-tools-debuginfo - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-tools-devel - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
perf - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
perf-debuginfo - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-extra-modules - update to 6.6.0-145.3.29.160
linux (Ubuntu package) - addressed in versions 7.0.0-31.31, 7.0.0-31.31.1, 7.0.0-31.31~24.04.1, 7.0.0-1006.7, 7.0.0-1011.11~24.04.1, 7.0.0-1012.12, 7.0.0-1012.12~24.04.1
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1013.13

• https://git.kernel.org/stable/c/08c600b7e1818539ba5efee4cdb06215c245ca78
• https://git.kernel.org/stable/c/5f6f2241034f189c69d4d0b5f8fe24a0c25b0c14
• https://git.kernel.org/stable/c/b84e002e0df26bbc6cbd3ca01b8212601fe0ae7d
• https://git.kernel.org/stable/c/c6c484a7d5bff6b929a86d7ed5130f29834c6a0d
• https://git.kernel.org/stable/c/e3d9c7160d483fc8f9e225aafad8ecbbc43f3151
• https://git.kernel.org/stable/c/ee2216dbdf0c677e89bb43e03247dba590ed00ef
• https://git.kernel.org/stable/c/f511807feee7cb29b61bdfa86472c7e9e2e5df94
• https://git.kernel.org/stable/c/f80add1bfb3425100a325b14f19648e75669a954

• Improper input validation in Linux kernel smb client
• openEuler 22.03 LTS SP4 update for kernel
• Red Hat Enterprise Linux 8 update for kernel-rt
• Anolis OS update for kernel:4.18
• openEuler 24.03 LTS SP3 update for kernel
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux
• Ubuntu update for linux-gcp-7.0