CVE-2020-25670Public exploit

Local kernel panic via LLCP reference leak

Published May 26, 2021 · Updated Aug 4, 2024

Use-after-free in Linux Kernel NFC LLCP allows local users to crash the system by repeatedly binding a crafted LLCP socket. The llcp_sock_bind() failure paths retain the reference acquired by nfc_llcp_local_get() when allocation fails or no LLCP service access point is available, allowing repeated binds to wrap the reference count. A local low-privileged account must be able to create NFC LLCP sockets; successful triggering causes a kernel panic, while privilege escalation remains unverified.

CVSS severity7.8
High
EPSS probability0.59%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux Kernel NFC LLCP allows local users to crash the system by repeatedly binding a crafted LLCP socket. The llcp_sock_bind() failure paths retain the reference acquired by nfc_llcp_local_get() when allocation fails or no LLCP service access point is available, allowing repeated binds to wrap the reference count. A local low-privileged account must be able to create NFC LLCP sockets; successful triggering causes a kernel panic, while privilege escalation remains unverified.

The record

CVE
CVE-2020-25670
Published
May 26, 2021
Updated
Aug 4, 2024
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 26, 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 privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=All

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.2NIST NVDAV:L/AC:L/Au:N/C:C/I:C/A:C

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 exploitPublished

Weakness, pattern, technique

CWE-416Use After Free
T1499.004Application or System Exploitation

Public exploit references

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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