---
id: "CVE-2026-98887"
kind: "vulnerability"
aliases: ["CVE-2026-98887"]
title: "Linux kernel: short mac80211_hwsim netlink attribute is read past its end"
severity: "unknown"
cvss: null
epss: 0.00215
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["linux-kernel", "mac80211-hwsim", "runtime", "wifi"]
not_affected_if: ["default-config", "module-not-loaded"]
published_at: "2026-10-23T12:18:22+00:00"
first_seen_at: "2026-10-23T21:57:33+00:00"
updated_at: "2026-10-25T12:38:51+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98887", "first_seen_at": "2026-10-23T21:57:33+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-98887", "first_seen_at": "2026-10-25T12:38:51+00:00"}]
---

# Linux kernel: short mac80211_hwsim netlink attribute is read past its end

The mac80211_hwsim wireless test driver in the Linux kernel trusts the length of a netlink attribute and reads eight-byte rate entries from it without checking the size. A short or empty attribute makes the read run past the buffer, which can crash the kernel or leak adjacent memory.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- unknown

## Fix

- Update to a Linux kernel release that includes the upstream commit rejecting undersized HWSIM_ATTR_TX_INFO; the sources do not list the fixed version numbers.

## Timeline

- 2026-10-23T21:57:33+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98887
- 2026-10-25T12:38:51+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-98887

## From the sources

In the Linux kernel, the following vulnerability has been resolved:

wifi: mac80211_hwsim: reject undersized HWSIM_ATTR_TX_INFO

hwsim_tx_info_frame_received_nl() casts the HWSIM_ATTR_TX_INFO payload
to a struct hwsim_tx_rate * and unconditionally reads
IEEE80211_TX_MAX_RATES entries (8 bytes) from it. The policy only bounds
the attribute from above (NLA_BINARY .len is a maximum) and the op sets
GENL_DONT_VALIDATE_STRICT, so a short or zero-length attribute is
accepted and the loop reads past the payload.

Require the exact length in the policy, so a malformed attribute is
rejected before the handler runs.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_