CVE-2026-63932
Received Received - Intake

Buffer Overflow in Linux Kernel IIO MHZ19B Driver

Publication date: 2026-07-19

Last updated on: 2026-07-19

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: iio: chemical: mhz19b: reject oversized serial replies mhz19b_receive_buf() appends each serdev chunk into the fixed MHZ19B_CMD_SIZE receive buffer and advances buf_idx by len without checking that the chunk fits in the remaining space. A large callback can therefore overflow st->buf before the command path validates the reply. Reset the reply state before each command and reject oversized serial replies before copying them into the fixed buffer. When an oversized reply is detected, wake the waiter and report -EMSGSIZE instead of overwriting st->buf.

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Meta Information

Published
2026-07-19
Last Modified
2026-07-19
Generated
2026-07-20
AI Q&A
2026-07-19
EPSS Evaluated
N/A
NVD
CVE-2026-63932
EUVD
EUVD-2026-45705

Affected Vendors & Products

Currently, no data is known.

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Exploitability

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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This is a buffer overflow vulnerability in the Linux kernel's IIO chemical sensor driver for the MH-Z19B CO2 sensor. The mhz19b_receive_buf function does not check if incoming serial data fits into a fixed-size receive buffer before copying it, allowing an attacker to overflow the buffer by sending oversized replies.

Detection Guidance

This vulnerability is specific to the Linux kernel's IIO subsystem, particularly the MH-Z19B CO2 sensor driver. Detection requires checking kernel logs for buffer overflow errors or unusual serial device behavior. Monitor dmesg for MHZ19B-related errors or system crashes after serial device interactions.

Impact Analysis

If exploited, this could allow local attackers with physical or serial port access to cause memory corruption, potentially leading to system crashes, privilege escalation, or arbitrary code execution. It may also enable denial-of-service conditions on systems using the MH-Z19B sensor.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards. It is a buffer overflow issue in the Linux kernel's IIO chemical sensor driver (mhz19b) that could lead to memory corruption or crashes, but there is no evidence it involves data exposure or privacy violations relevant to these regulations.

Mitigation Strategies

Update your Linux kernel to a patched version that includes the fix for CVE-2026-63932. If immediate patching is not possible, disable the MH-Z19B driver or restrict access to the serial device to trusted users only.

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