Out-of-bounds write in Linux kernel - CVE-2026-89652

Vulnerability identifier: #VU149150

CSH Severity: Low

CVSS v4: 2.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-89652

CWE-ID: CWE-787

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote user to cause memory corruption.

The vulnerability exists due to improper bounds checking in the CephFS NFS-export get_name functions when processing LOOKUPNAME replies containing oversized dentry names. A remote user can return a specially crafted LOOKUPNAME reply to cause memory corruption.

The issue is reachable when a CephFS mount is re-exported over NFS.

Linux kernel
Debian Linux
openEuler
Ubuntu
linux-nvidia-tegra (Ubuntu package)
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)
bpftool
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
linux (Debian package)

Install security update from vendor's repository.

linux-nvidia-tegra (Ubuntu package) - update to 6.8.0-1038.42
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
bpftool - addressed in versions 5.10.0-334.0.0.235, 6.6.0-145.1.28.165
kernel - addressed in versions 5.10.0-334.0.0.235, 6.6.0-145.1.28.165
python3-perf-debuginfo - addressed in versions 5.10.0-334.0.0.235, 6.6.0-145.1.28.165
python3-perf - addressed in versions 5.10.0-334.0.0.235, 6.6.0-145.1.28.165
perf-debuginfo - addressed in versions 5.10.0-334.0.0.235, 6.6.0-145.1.28.165
perf - addressed in versions 5.10.0-334.0.0.235, 6.6.0-145.1.28.165
kernel-tools-devel - addressed in versions 5.10.0-334.0.0.235, 6.6.0-145.1.28.165
kernel-tools-debuginfo - addressed in versions 5.10.0-334.0.0.235, 6.6.0-145.1.28.165
kernel-tools - addressed in versions 5.10.0-334.0.0.235, 6.6.0-145.1.28.165
kernel-source - addressed in versions 5.10.0-334.0.0.235, 6.6.0-145.1.28.165
kernel-headers - addressed in versions 5.10.0-334.0.0.235, 6.6.0-145.1.28.165
kernel-devel - addressed in versions 5.10.0-334.0.0.235, 6.6.0-145.1.28.165
kernel-debugsource - addressed in versions 5.10.0-334.0.0.235, 6.6.0-145.1.28.165
kernel-debuginfo - addressed in versions 5.10.0-334.0.0.235, 6.6.0-145.1.28.165
bpftool-debuginfo - addressed in versions 5.10.0-334.0.0.235, 6.6.0-145.1.28.165
linux (Debian package) - update to 6.12.111-1

• https://git.kernel.org/stable/c/06fb5e623cdc2402d6bb29be94d9beb9a826ffec
• https://git.kernel.org/stable/c/61d9f27b191b838b96b697ce0bfaee39a138243a
• https://git.kernel.org/stable/c/e7c2fd3893a7f7fcd7e8cf0b2c6348bb1e893df6
• https://git.kernel.org/stable/c/eff8013c5a8916613c742ae5a2cc341cb605c0ae

• Out-of-bounds write in Linux kernel ceph
• openEuler 22.03 LTS SP4 update for kernel
• 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
• Ubuntu update for linux-nvidia-tegra