CVE-2021-47540

Kernel crash via unchecked HE capability pointer

Published May 24, 2024 · Updated May 11, 2026

NULL pointer dereference in the Linux mt7915 wireless driver allows local users to crash the kernel by creating an IBSS interface. mt7915_get_phy_mode unconditionally reads he_cap->has_he after ieee80211_get_he_iftype_cap returns NULL for an interface without HE capabilities. Reachability requires local access, an MT7915 wireless device, and creation of an IBSS interface; the resulting kernel oops interrupts service.

CVSS severity5.5
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in the Linux mt7915 wireless driver allows local users to crash the kernel by creating an IBSS interface. mt7915_get_phy_mode unconditionally reads he_cap->has_he after ieee80211_get_he_iftype_cap returns NULL for an interface without HE capabilities. Reachability requires local access, an MT7915 wireless device, and creation of an IBSS interface; the resulting kernel oops interrupts service.

The record

CVE
CVE-2021-47540
Published
May 24, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 24, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.8
  2. Affected versionversion=e57b7901469fc0b021930b83a8094baaf3d81b09 <14b03b8cebdf18ff13c39d58501b625411314de2
  3. Affected versionversion=e57b7901469fc0b021930b83a8094baaf3d81b09 <6e53d6d26920d5221d3f4d4f5ffdd629ea69aa5c
  4. Affected versionversion=e57b7901469fc0b021930b83a8094baaf3d81b09 <932b338f4e5c4cb0c2ed640da3bced1e63620198

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.8; version=e57b7901469fc0b021930b83a8094baaf3d81b09 <14b03b8cebdf18ff13c39d58501b625411314de2; version=e57b7901469fc0b021930b83a8094baaf3d81b09 <6e53d6d26920d5221d3f4d4f5ffdd629ea69aa5c; version=e57b7901469fc0b021930b83a8094baaf3d81b09 <932b338f4e5c4cb0c2ed640da3bced1e63620198

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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