rootpwn

high · CVSS v3 7

CVE-2026-98029

This vulnerability in the Linux kernel's nfp driver allows a local user to read beyond the allocated buffer when querying flow steering rule

Overview

This vulnerability in the Linux kernel's nfp driver allows a local user to read beyond the allocated buffer when querying flow steering rules via ETHTOOL_GRXCLSRLALL. The flaw occurs because the driver dumps all ntuple rule entries without respecting the caller-provided buffer size, leading to a buffer over-read. It can be exploited by any user on a system with flow steering rules configured, potentially exposing kernel memory contents.

Description

In the Linux kernel, the following vulnerability has been resolved: eth: nfp: bound the ntuple rule dump by the caller's buffer size nfp_net_get_fs_loc() dumps every entry of nn->fs.list into rule_locs[] without consulting cmd->rule_cnt, which is how many 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 flow steering 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. Bail out with -EMSGSIZE when the buffer fills up, the way the other ntuple capable drivers do, and report how many locations were filled so a shrinking rule list does not leave the caller reading stale slots.

Impact

Confidentiality: potential leakage of kernel memory contents. Integrity: not directly affected, but information disclosure could aid further attacks. Availability: no direct impact. Impacted parties: local users on systems with flow steering rules and administrators who manage those rules.

Remediation

Apply the kernel patch that bounds the ntuple rule dump by cmd->rule_cnt, or upgrade to a kernel version where the issue is fixed. If a patch is not yet available, restrict ETHTOOL_GRXCLSRLALL usage to privileged users or disable flow steering rules until a fix is applied.

Risk context

High severity, CVSS 7.0, no EPSS data available. Defenders should treat this as a medium‑high risk issue and prioritize patching or mitigation accordingly.

Affected products

  • Linux kernel
  • nfp driver
  • ethtool
  • Intel NFP
  • Netronome NFP

Scores

Severity
high
CVSS v2
6
CVSS v3
7
CVSS v4
—
EPSS
—

kernel nfp ethtool buffer-overread local information-disclosure high-severity

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