SB2026072138 - Out-of-bounds read in Linux kernel fbdev core driver

Description

This security bulletin contains information about 1 vulnerability.

1) Out-of-bounds read (CVE-ID: CVE-2026-53402)

CWE-ID: CWE-125 - Out-of-bounds read

CVSSv4: 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]

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.

Remediation

Install update from vendor's website.

References

• 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