CVE-2020-25672

Local denial of service via failed LLCP connections

Published May 25, 2021 · Updated Aug 4, 2024

Memory leak in the Linux kernel NFC LLCP implementation allows local users to exhaust memory through repeated failed connections. In llcp_sock_connect(), kmemdup allocates service_name, but the sock_unlink error path returns without freeing it when nfc_llcp_send_connect() fails. Exploitation requires local execution and a usable NFC LLCP socket; repeated failures consume kernel memory and can interrupt the host.

CVSS severity7.5
High
EPSS probability3.13%
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 the Linux kernel NFC LLCP implementation allows local users to exhaust memory through repeated failed connections. In llcp_sock_connect(), kmemdup allocates service_name, but the sock_unlink error path returns without freeing it when nfc_llcp_send_connect() fails. Exploitation requires local execution and a usable NFC LLCP socket; repeated failures consume kernel memory and can interrupt the host.

The record

CVE
CVE-2020-25672
Published
May 25, 2021
Updated
Aug 4, 2024
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-401, T1499
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 25, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=All

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=All

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-401Missing Release of Memory after Effective Lifetime
T1499Endpoint Denial of Service

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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