CVE-2021-46924

Kernel memory exhaustion via unreleased NFC buffer

Published Feb 27, 2024 · Updated May 11, 2026

Memory leak in affected Linux kernel st21nfca NFC driver versions allows local users to exhaust kernel memory through device handling. The st21nfca_hci_i2c_probe path allocates phy->pending_skb, but neither its error path nor the device-removal path releases the buffer. Reachability requires the st21nfca driver and compatible NFC I2C hardware; public records do not identify a user-controlled trigger, and repeated lifecycle events consume kernel memory.

CVSS severity5.5
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leak in affected Linux kernel st21nfca NFC driver versions allows local users to exhaust kernel memory through device handling. The st21nfca_hci_i2c_probe path allocates phy->pending_skb, but neither its error path nor the device-removal path releases the buffer. Reachability requires the st21nfca driver and compatible NFC I2C hardware; public records do not identify a user-controlled trigger, and repeated lifecycle events consume kernel memory.

The record

CVE
CVE-2021-46924
Published
Feb 27, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-401
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 27, 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=3.16
  2. Affected versionversion=68957303f44a501af5cf37913208a2acaa6bcdf1 <1b9dadba502234eea7244879b8d5d126bfaf9f0c
  3. Affected versionversion=68957303f44a501af5cf37913208a2acaa6bcdf1 <1cd4063dbc91cf7965d73a6a3855e2028cd4613b
  4. Affected versionversion=68957303f44a501af5cf37913208a2acaa6bcdf1 <238920381b8925d070d32d73cd9ce52ab29896fe
  5. Affected versionversion=68957303f44a501af5cf37913208a2acaa6bcdf1 <38c3e320e7ff46f2dc67bc5045333e63d9f8918d
  6. Affected versionversion=68957303f44a501af5cf37913208a2acaa6bcdf1 <a1e0080a35a16ce3808f7040fe0c3a8fdb052349
  7. Affected versionversion=68957303f44a501af5cf37913208a2acaa6bcdf1 <e553265ea56482da5700f56319fda9ff53e7dcb4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3.16; version=68957303f44a501af5cf37913208a2acaa6bcdf1 <1b9dadba502234eea7244879b8d5d126bfaf9f0c; version=68957303f44a501af5cf37913208a2acaa6bcdf1 <1cd4063dbc91cf7965d73a6a3855e2028cd4613b; version=68957303f44a501af5cf37913208a2acaa6bcdf1 <238920381b8925d070d32d73cd9ce52ab29896fe; version=68957303f44a501af5cf37913208a2acaa6bcdf1 <38c3e320e7ff46f2dc67bc5045333e63d9f8918d; version=68957303f44a501af5cf37913208a2acaa6bcdf1 <a1e0080a35a16ce3808f7040fe0c3a8fdb052349; version=68957303f44a501af5cf37913208a2acaa6bcdf1 <e553265ea56482da5700f56319fda9ff53e7dcb4

Published CVSS scores

5.5NIST National Vulnerability DatabaseCVSS: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-401Missing Release of Memory after Effective Lifetime

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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