Out-of-bounds read in Linux kernel - CVE-2026-64324

Vulnerability identifier: #VU139662

CSH Severity: Low

CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-64324

CWE-ID: CWE-125

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to an out-of-bounds read in udf_free_blocks() and block bitmap handling in fs/udf/balloc.c when processing crafted UDF filesystem block extents. A local user can supply a crafted filesystem and truncate a writable file on it to cause a denial of service.

On systems where active users can mount removable UDF media without administrative privileges, user interaction is not required beyond mounting the media and truncating a file.

Linux kernel
openEuler
Ubuntu
bpftool
python3-perf-debuginfo
python3-perf
perf-debuginfo
perf
kernel-tools-devel
kernel-tools-debuginfo
kernel-tools
kernel-headers
kernel-extra-modules
kernel-devel
kernel-debugsource
kernel-debuginfo
bpftool-debuginfo
kernel
kernel-source
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 - update to 6.6.0-145.3.29.160
python3-perf-debuginfo - update to 6.6.0-145.3.29.160
python3-perf - update to 6.6.0-145.3.29.160
perf-debuginfo - update to 6.6.0-145.3.29.160
perf - update to 6.6.0-145.3.29.160
kernel-tools-devel - update to 6.6.0-145.3.29.160
kernel-tools-debuginfo - update to 6.6.0-145.3.29.160
kernel-tools - update to 6.6.0-145.3.29.160
kernel-headers - update to 6.6.0-145.3.29.160
kernel-extra-modules - update to 6.6.0-145.3.29.160
kernel-devel - update to 6.6.0-145.3.29.160
kernel-debugsource - update to 6.6.0-145.3.29.160
kernel-debuginfo - update to 6.6.0-145.3.29.160
bpftool-debuginfo - update to 6.6.0-145.3.29.160
kernel - update to 6.6.0-145.3.29.160
kernel-source - 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/12af328d2ee8d68e81ba612246d0b54b22d23e1f
• https://git.kernel.org/stable/c/335202ab25b01fdd45889ff25eab70864686dea3
• https://git.kernel.org/stable/c/5f0419457f89dce1a3f1c8e62a3adf2f39ab8168
• https://git.kernel.org/stable/c/9442d75429b0c556292a7454fe888d54259f5240
• https://git.kernel.org/stable/c/b54aee5652fcd7c23a0904a4623ec462c3edc70c
• https://git.kernel.org/stable/c/be87de7789a82a030a4896bc7683415ec9fa6f2b
• https://git.kernel.org/stable/c/fb49099206c5c57af28a157249fa7bcb5518f99e
• https://git.kernel.org/stable/c/fdd6229d2ae9914c1f25d1041db0f4f312a4fa76

• Out-of-bounds read in Linux kernel udf
• 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