CVE-2026-98236

Received Received - Intake

BaseFortify

Publication date: 2026-10-06

Last updated on: 2026-10-19

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: net: wwan: mhi_wwan_mbim: check skb_copy_bits() return value mhi_mbim_rx() ignores the return value of skb_copy_bits() when it copies each datagram out of the NTB. The datagram offset and length come from the DPE, which is only checked to lie within the NTB itself, so a modem can point a datagram outside the received skb. The copy then fails and the freshly allocated skbn is passed to netif_rx() with its uninitialized contents still in place, leaking kernel heap memory into the network stack. Free the skb and account an error when the copy fails. Verified in a QEMU guest with a fault injector pointing a DPE outside the received NTB: the copy fails, and the unpatched driver hands the uninitialized skbn to the network stack (observed as "unknown protocol" on bytes that were never written). With this check the failed datagram is dropped and counted as an rx error. Changes in v2: factor the free-and-count sequence out into mhi_mbim_rx_drop(), shared with the unknown-protocol path, as suggested by Loic Poulain.

CVSS Scores

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Meta Information

Published

2026-10-06

Last Modified

2026-10-19

Generated

2026-10-19

AI Q&A

2026-10-06

EPSS Evaluated

2026-10-18

NVD

CVE-2026-98236

EUVD

EUVD-2026-93164

Affected Vendors & Products

Vendor	Product	Version / Range
Linux	Linux	aa730a9905b7b079ef2fffdab7f15dbb842f5c7c
Linux	Linux	aa730a9905b7b079ef2fffdab7f15dbb842f5c7c
Linux	Linux	aa730a9905b7b079ef2fffdab7f15dbb842f5c7c
Linux	Linux	aa730a9905b7b079ef2fffdab7f15dbb842f5c7c
Linux	Linux	aa730a9905b7b079ef2fffdab7f15dbb842f5c7c
Linux	Linux	aa730a9905b7b079ef2fffdab7f15dbb842f5c7c
Linux	Linux	aa730a9905b7b079ef2fffdab7f15dbb842f5c7c
Linux	Linux	5.15

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves the mhi_wwan_mbim driver. It fails to check the return value of skb_copy_bits() when copying datagrams from the NTB. A malicious modem can point a datagram outside the received skb, causing the copy to fail. The driver then passes an uninitialized skb with kernel heap memory to the network stack, leaking sensitive data.

Detection Guidance

This vulnerability involves kernel heap memory leaks in the MHI WWAN MBIM driver. Detection requires checking for unusual network traffic patterns or kernel logs indicating uninitialized memory exposure. Monitor for 'unknown protocol' errors in network logs and inspect skb_copy_bits() failures in the mhi_wwan_mbim driver. No specific commands are provided in the context.

Impact Analysis

This vulnerability could allow an attacker to leak kernel heap memory into the network stack, potentially exposing sensitive information. It may also cause network errors or crashes if the uninitialized skb is processed incorrectly.

Compliance Impact

This vulnerability could potentially affect compliance with GDPR and HIPAA by enabling unauthorized disclosure of kernel heap memory contents through network traffic. If exploited, it may lead to exposure of sensitive data, violating confidentiality requirements under these regulations.

Mitigation Strategies

Apply the kernel patch that adds a check for skb_copy_bits() return value in the mhi_wwan_mbim driver. Free the skb and account an error when the copy fails to prevent memory leaks. Update to a Linux kernel version containing this fix.

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