SB20260720351 - Integer underflow in Linux kernel tty serial driver

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Main Vulnerability Database SB20260720351

SB20260720351 - Integer underflow in Linux kernel tty serial driver

Published: July 20, 2026

Security Bulletin ID SB20260720351
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Information disclosure

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Integer underflow (CVE-ID: CVE-2026-63883)

CWE-ID: CWE-191 - Integer underflow

CVSSv4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a local user to disclose stale buffer data.

The vulnerability exists due to an integer underflow in qcom_geni_serial_handle_tx_dma() when handling a DMA completion interrupt after uart_flush_buffer() resets the transmit buffer. A local user can trigger a flush before DMA completion is processed to disclose stale buffer data.

The issue is caused by a race condition between transmit buffer flushing and delayed DMA completion handling.


Remediation

Install update from vendor's website.

References