Out-of-bounds read in Linux kernel - CVE-2026-64380

Vulnerability identifier: #VU139584

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-2026-64380

CWE-ID: CWE-125

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 out-of-bounds read in posix_info_sid_size() in the SMB client when parsing truncated POSIX SIDs. A remote attacker can send a specially crafted SMB response to cause a denial of service.

Linux kernel
openEuler
Ubuntu
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
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
bpftool - 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
python3-perf-debuginfo - 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
perf-debuginfo - 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
kernel-tools-devel - 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 - 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-headers - 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-debugsource - 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
bpftool-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/0de5b8e76847f5de26f364a82c6602c4881c30da
• https://git.kernel.org/stable/c/171605aed68380c2fa75dff9b3a1ed427c50065b
• https://git.kernel.org/stable/c/4213c1208978483021d7d125c131de3985d38f61
• https://git.kernel.org/stable/c/427eb7eb46425fec845a43e861f3d6e2899cae59
• https://git.kernel.org/stable/c/46a84715a015cb48e1b9c219dc88c03d8a541ea4
• https://git.kernel.org/stable/c/7ad2bcf2441430bb2e918fb3ef9a90d775a6e422
• https://git.kernel.org/stable/c/86c5d470f5d42e61123b2f4b4f0b91f4eee5b980
• https://git.kernel.org/stable/c/96e889bc1e759c83f25093e8c2f3da31b4973f30

• Out-of-bounds read in Linux kernel smb client
• openEuler 22.03 LTS SP4 update for kernel
• 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