SB20261022457 - Out-of-bounds read in Linux kernel tty vt driver

Description

This security bulletin contains information about 1 vulnerability.

1) Out-of-bounds read (CVE-ID: CVE-2026-98839)

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 potentially disclose sensitive kernel memory.

The vulnerability exists due to an unsigned integer underflow in paste_selection() in drivers/tty/vt/selection.c when a concurrent selection update replaces the selection buffer with a shorter buffer while a paste operation is sleeping. A local user can race a TIOCLINUX (TIOCL_SETSEL) ioctl against the paste operation to make vc_sel.buf_len smaller than the number of bytes already pasted, triggering an out-of-bounds read of up to 4094 bytes that may expose adjacent kernel memory through the terminal line discipline.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/037d7e3ca5c593092f4b0d471eb869a85cbddde0
• https://git.kernel.org/stable/c/39495ef5d6f8019e62d65807f217a7ca8232727a
• https://git.kernel.org/stable/c/619c6d7dd76fff15a9714fbf02ce299b737f01a2