CVE-2025-21669

Local kernel compromise via stale transport packets

Published Jan 31, 2025 · Updated Aug 5, 2026

Type confusion in Linux kernel AF_VSOCK handling allows local users to crash the host or compromise the kernel through stale packets. The virtio receive path accepts a packet after the socket has been de-assigned or moved to another transport, then uses a null or mismatched vsk->transport object. Unprivileged local access is sufficient when AF_VSOCK loopback support is enabled; no victim interaction is required.

CVSS severity7.8
High
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

Type confusion in Linux kernel AF_VSOCK handling allows local users to crash the host or compromise the kernel through stale packets. The virtio receive path accepts a packet after the socket has been de-assigned or moved to another transport, then uses a null or mismatched vsk->transport object. Unprivileged local access is sufficient when AF_VSOCK loopback support is enabled; no victim interaction is required.

The record

CVE
CVE-2025-21669
Published
Jan 31, 2025
Updated
Aug 5, 2026
Vendor
Siemens
Product
SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
Classifications
CWE-476, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 31, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=0 <*

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Siemens · SIMATIC S7-1500 TM MFP - GNU/Linux subsystemversion=0 <*
The Linux Kernel Organization · Linuxversion=5.5; version=c0cfa2d8a788fcf45df5bf4070ab2474c88d543a <18a7fc371d1dbf8deff16c2dd9292bcc73f43040; version=c0cfa2d8a788fcf45df5bf4070ab2474c88d543a <2cb7c756f605ec02ffe562fb26828e4bcc5fdfc1; version=c0cfa2d8a788fcf45df5bf4070ab2474c88d543a <6486915fa661584d70e8e7e4068c6c075c67dd6d; version=c0cfa2d8a788fcf45df5bf4070ab2474c88d543a <677579b641af109613564460a4e3bdcb16850b61; version=c0cfa2d8a788fcf45df5bf4070ab2474c88d543a <88244163bc7e7b0ce9dd7bf4c8a563b41525c3ee; version=c0cfa2d8a788fcf45df5bf4070ab2474c88d543a <d88b249e14bd0ee1e46bbe4f456e22e01b8c68de

Published CVSS scores

7.8Linux Kernel CVE TeamCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5Siemens ProductCERTCVSS: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
T1068Exploitation for Privilege Escalation

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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