CVE-2026-98027

Received Received - Intake

BaseFortify

Publication date: 2026-09-25

Last updated on: 2026-10-03

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: net: dsa: mv88e6xxx: bound the policy rule dump by the caller's buffer size mv88e6xxx_get_rxnfc() uses rxnfc->rule_cnt as the write index while dumping the policy IDR, clobbering the input value before it has been looked at. That input is the number of entries the caller had room for. ETHTOOL_GRXCLSRLALL requires no CAP_NET_ADMIN and the ioctl sizes the buffer from the rule_cnt userspace passes in, so once an admin has installed policy rules any user can ask for fewer slots than there are rules and run off the end of the allocation. A rule_cnt of 0 leaves the buffer pointer NULL and the walk dereferences it. Count into a local so the caller's limit survives the walk, and stop with -EMSGSIZE once it is reached.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-09-25

Last Modified

2026-10-03

Generated

2026-10-15

AI Q&A

2026-09-25

EPSS Evaluated

2026-10-14

NVD

CVE-2026-98027

EUVD

EUVD-2026-86680

Affected Vendors & Products

Vendor	Product	Version / Range
Linux	Linux	da7dc87553046a43be1620a783ce3d9f6583d322
Linux	Linux	da7dc87553046a43be1620a783ce3d9f6583d322
Linux	Linux	da7dc87553046a43be1620a783ce3d9f6583d322
Linux	Linux	da7dc87553046a43be1620a783ce3d9f6583d322
Linux	Linux	da7dc87553046a43be1620a783ce3d9f6583d322
Linux	Linux	da7dc87553046a43be1620a783ce3d9f6583d322
Linux	Linux	da7dc87553046a43be1620a783ce3d9f6583d322
Linux	Linux	da7dc87553046a43be1620a783ce3d9f6583d322
Linux	Linux	5.4

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves a buffer overflow in the mv88e6xxx network driver. The function mv88e6xxx_get_rxnfc() incorrectly uses the caller's buffer size as a write index while dumping policy rules, potentially overwriting memory and causing crashes or privilege escalation.

Detection Guidance

This vulnerability can be detected by checking for unauthorized access attempts or crashes in systems using the mv88e6xxx network driver. Monitor logs for ETHTOOL_GRXCLSRLALL ioctl calls with unusual rule_cnt values. No specific commands are provided in the context.

Impact Analysis

An attacker could exploit this to crash the system or gain elevated privileges. Since no CAP_NET_ADMIN is required, any user can trigger the flaw by requesting fewer rules than exist, leading to memory corruption.

Compliance Impact

This vulnerability allows local users to read kernel memory beyond allocated buffers, potentially exposing sensitive data. For GDPR, this could violate principles of data minimization and security. HIPAA may be affected if protected health information is exposed. The high impact on confidentiality, integrity, and availability suggests potential non-compliance with security requirements in these regulations.

Mitigation Strategies

Update the Linux kernel to a patched version that resolves this issue. Restrict access to ETHTOOL_GRXCLSRLALL ioctl calls if possible. Monitor for policy rule misuse until patched.

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