Out-of-bounds read in Linux kernel - CVE-2026-89537

Vulnerability identifier: #VU149271

CSH Severity: Medium

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

CVE-ID: CVE-2026-89537

CWE-ID: CWE-125

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to read memory out of bounds.

The vulnerability exists due to improper length validation in gss_krb5_verify_mic_v2() when verifying a short RFC 4121 MIC token. A remote attacker can supply a short MIC token to read memory out of bounds.

Linux kernel
SUSE Linux Enterprise Server 12 SP5 LTSS Extended
SUSE Linux Enterprise Server 12 SP5
Debian Linux
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise High Performance Computing 12
SUSE Linux Micro Extras
SUSE Linux Micro
SUSE Linux Enterprise Live Patching
Ubuntu
linux (Ubuntu package)
linux-oracle (Ubuntu package)
linux-gcp (Ubuntu package)
linux-aws (Ubuntu package)
linux-ibm (Ubuntu package)
linux-hwe-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
kgraft-patch-4_12_14-122_339-default
kernel-default-kgraft
gfs2-kmp-default
ocfs2-kmp-default
gfs2-kmp-default-debuginfo
kernel-default-base
kernel-default-base-debuginfo
dlm-kmp-default
kernel-default-devel
dlm-kmp-default-debuginfo
kernel-syms
ocfs2-kmp-default-debuginfo
cluster-md-kmp-default-debuginfo
kernel-default-kgraft-devel
kernel-default-debugsource
kernel-default-debuginfo
kernel-default
cluster-md-kmp-default
kernel-default-devel-debuginfo
kernel-source
kernel-macros
kernel-devel
kernel-default-man
kernel-64kb
kernel-64kb-debugsource
kernel-64kb-devel
kernel-obs-build
kernel-obs-build-debugsource
linux (Debian package)

Install security update from vendor's repository.

linux (Ubuntu package) - update to 7.0.0-42.42
linux-oracle (Ubuntu package) - update to 7.0.0-1015.16
linux-gcp (Ubuntu package) - update to 7.0.0-1016.18
linux-aws (Ubuntu package) - update to 7.0.0-1016.17
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
kgraft-patch-4_12_14-122_339-default - update to 1-8.3.1
kernel-default-kgraft - update to 4.12.14-122.339.1
gfs2-kmp-default - update to 4.12.14-122.339.1
ocfs2-kmp-default - update to 4.12.14-122.339.1
gfs2-kmp-default-debuginfo - update to 4.12.14-122.339.1
kernel-default-base - update to 4.12.14-122.339.1
kernel-default-base-debuginfo - update to 4.12.14-122.339.1
dlm-kmp-default - update to 4.12.14-122.339.1
kernel-default-devel - addressed in versions 4.12.14-122.339.1, 6.4.0-159998.55.1
dlm-kmp-default-debuginfo - update to 4.12.14-122.339.1
kernel-syms - addressed in versions 4.12.14-122.339.1, 6.4.0-159998.55.1
ocfs2-kmp-default-debuginfo - update to 4.12.14-122.339.1
cluster-md-kmp-default-debuginfo - update to 4.12.14-122.339.1
kernel-default-kgraft-devel - update to 4.12.14-122.339.1
kernel-default-debugsource - addressed in versions 4.12.14-122.339.1, 6.4.0-159998.55.1
kernel-default-debuginfo - update to 4.12.14-122.339.1
kernel-default - addressed in versions 4.12.14-122.339.1, 6.4.0-159998.55.1
cluster-md-kmp-default - update to 4.12.14-122.339.1
kernel-default-devel-debuginfo - addressed in versions 4.12.14-122.339.1, 6.4.0-159998.55.1
kernel-source - update to 4.12.14-122.339.1
kernel-macros - update to 4.12.14-122.339.1
kernel-devel - update to 4.12.14-122.339.1
kernel-default-man - update to 4.12.14-122.339.1
kernel-64kb - update to 6.4.0-159998.55.1
kernel-64kb-debugsource - update to 6.4.0-159998.55.1
kernel-64kb-devel - update to 6.4.0-159998.55.1
kernel-obs-build - update to 6.4.0-159998.55.1
kernel-obs-build-debugsource - update to 6.4.0-159998.55.1
linux (Debian package) - update to 6.12.115-2

• https://git.kernel.org/stable/c/7a946b2e7207f968902f2147ab9b30726f82f7ab
• https://git.kernel.org/stable/c/b94f6719dcd9f7a609bc5f459f85795900e77d25

• Out-of-bounds read in Linux kernel sunrpc auth_gss
• Debian update for linux
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more
• SUSE update for the Linux Kernel
• SUSE update for the Linux Kernel