Out-of-bounds read in Linux kernel - CVE-2026-53402

Vulnerability identifier: #VU138862

CSH Severity: Low

CVSS v4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-53402

CWE-ID: CWE-125

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to disclose sensitive information.

The vulnerability exists due to an out-of-bounds read in fbcon_do_set_font() and subsequent rendering in the fbcon console subsystem when handling a failed font change rollback and later rendering user-controlled character indices. A local user can trigger a font change failure and then supply character indices greater than 255 to disclose sensitive information.

Exploitation requires a failure in the font-setting error path that leaves the console state desynchronized after vc_resize() fails.

Linux kernel
Debian Linux
openEuler
kernel
bpftool
bpftool-debuginfo
kernel-debuginfo
kernel-debugsource
kernel-devel
kernel-headers
kernel-source
kernel-tools
kernel-tools-debuginfo
kernel-tools-devel
perf
perf-debuginfo
python3-perf
python3-perf-debuginfo
linux (Debian package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel - update to 5.10.0-329.0.0.230
bpftool - update to 5.10.0-329.0.0.230
bpftool-debuginfo - update to 5.10.0-329.0.0.230
kernel-debuginfo - update to 5.10.0-329.0.0.230
kernel-debugsource - update to 5.10.0-329.0.0.230
kernel-devel - update to 5.10.0-329.0.0.230
kernel-headers - update to 5.10.0-329.0.0.230
kernel-source - update to 5.10.0-329.0.0.230
kernel-tools - update to 5.10.0-329.0.0.230
kernel-tools-debuginfo - update to 5.10.0-329.0.0.230
kernel-tools-devel - update to 5.10.0-329.0.0.230
perf - update to 5.10.0-329.0.0.230
perf-debuginfo - update to 5.10.0-329.0.0.230
python3-perf - update to 5.10.0-329.0.0.230
python3-perf-debuginfo - update to 5.10.0-329.0.0.230
linux (Debian package) - update to 6.12.96-1

• https://git.kernel.org/stable/c/076b1aa65f77a49bce5a48a4a55a397cfcafa2b8
• https://git.kernel.org/stable/c/39815715cbcfabb16fc8c5f4a23deeda20f5df62
• https://git.kernel.org/stable/c/8fdc8c2057eea08d40ce2c8eed41ff9e451c65c2
• https://git.kernel.org/stable/c/b5bb2c696e140c399cb874def2feedf61dee27d6

• Out-of-bounds read in Linux kernel fbdev core driver
• Debian update for linux
• openEuler 22.03 LTS SP4 update for kernel