Integer overflow in Linux kernel - CVE-2026-89634

Vulnerability identifier: #VU149163

CSH Severity: Medium

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

CVE-ID: CVE-2026-89634

CWE-ID: CWE-190

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 an integer overflow in symlink_data() in fs/smb/client/smb2file.c when processing an SMB error context with a malformed ErrorDataLength value. A remote attacker can provide a crafted SMB error context to cause a denial of service.

Linux kernel
Debian Linux
openEuler
Ubuntu
linux (Ubuntu package)
linux-aws (Ubuntu package)
linux-gcp (Ubuntu package)
linux-oracle (Ubuntu package)
linux-ibm (Ubuntu package)
linux-hwe-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
kernel
python3-perf-debuginfo
python3-perf
perf-debuginfo
perf
kernel-tools-devel
kernel-tools-debuginfo
kernel-tools
kernel-source
kernel-headers
kernel-devel
kernel-debugsource
kernel-debuginfo
bpftool-debuginfo
bpftool
linux (Debian package)

Install security update from vendor's repository.

linux (Ubuntu package) - update to 7.0.0-42.42
linux-aws (Ubuntu package) - update to 7.0.0-1016.17
linux-gcp (Ubuntu package) - update to 7.0.0-1016.18
linux-oracle (Ubuntu package) - update to 7.0.0-1015.16
linux-ibm (Ubuntu package) - update to 7.0.0-1017.17
linux-hwe-7.0 (Ubuntu package) - update to 7.0.0-42.42~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1017.17
kernel - update to 6.6.0-145.1.28.165
python3-perf-debuginfo - update to 6.6.0-145.1.28.165
python3-perf - update to 6.6.0-145.1.28.165
perf-debuginfo - update to 6.6.0-145.1.28.165
perf - update to 6.6.0-145.1.28.165
kernel-tools-devel - update to 6.6.0-145.1.28.165
kernel-tools-debuginfo - update to 6.6.0-145.1.28.165
kernel-tools - update to 6.6.0-145.1.28.165
kernel-source - update to 6.6.0-145.1.28.165
kernel-headers - update to 6.6.0-145.1.28.165
kernel-devel - update to 6.6.0-145.1.28.165
kernel-debugsource - update to 6.6.0-145.1.28.165
kernel-debuginfo - update to 6.6.0-145.1.28.165
bpftool-debuginfo - update to 6.6.0-145.1.28.165
bpftool - update to 6.6.0-145.1.28.165
linux (Debian package) - update to 6.12.111-1

• https://git.kernel.org/stable/c/1f824f61d1df52392eaf0b74dfa5659d724fde30
• https://git.kernel.org/stable/c/62656b024efc21c3230eade1a847f25871c3d2bb
• https://git.kernel.org/stable/c/62a3025983c8c735a3c6fc85a59316f31b59af07
• https://git.kernel.org/stable/c/657372ba6ea50b4474d2a6a610097eae8cd1f3e9

• Integer overflow in Linux kernel smb client
• Debian update for linux
• openEuler 24.03 LTS SP1 update for kernel
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more