CVE-2025-21719

Kernel crash via unresolved multicast route dump

Published Feb 27, 2025 · Updated Aug 5, 2026

Improper input validation in Linux IPv4 multicast-routing code allows local users to crash affected kernels during a route dump. mr_table_dump calls mr_mfc_uses_dev on an unresolved forwarding-cache entry, causing queue pointers to be read as minvif and maxvif indexes. A low-privileged local user must reach the rtnetlink dump path while such an entry exists; the invalid access can interrupt the host or embedded subsystem.

CVSS severity5.5
Medium
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Linux IPv4 multicast-routing code allows local users to crash affected kernels during a route dump. mr_table_dump calls mr_mfc_uses_dev on an unresolved forwarding-cache entry, causing queue pointers to be read as minvif and maxvif indexes. A low-privileged local user must reach the rtnetlink dump path while such an entry exists; the invalid access can interrupt the host or embedded subsystem.

The record

CVE
CVE-2025-21719
Published
Feb 27, 2025
Updated
Aug 5, 2026
Vendor
Siemens
Product
SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
Classifications
CWE-20, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 27, 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=4.20; version=cb167893f41e21e6bd283d78e53489289dc0592d <15a901361ec3fb1c393f91880e1cbf24ec0a88bd; version=cb167893f41e21e6bd283d78e53489289dc0592d <26bb7d991f04eeef47dfad23e533834995c26f7a; version=cb167893f41e21e6bd283d78e53489289dc0592d <53df27fd38f84bd3cd6b004eb4ff3c4903114f1d; version=cb167893f41e21e6bd283d78e53489289dc0592d <547ef7e8cbb98f966c8719a3e15d4e078aaa9b47; version=cb167893f41e21e6bd283d78e53489289dc0592d <57177c5f47a8da852f8d76cf6945cf803f8bb9e5; version=cb167893f41e21e6bd283d78e53489289dc0592d <71a0fcb68c0a5f3ec912b540cd5d72148e6ee5f1; version=cb167893f41e21e6bd283d78e53489289dc0592d <a099834a51ccf9bbba3de86a251b3433539abfde; version=cb167893f41e21e6bd283d78e53489289dc0592d <b379b3162ff55a70464c6a934ae9bf0497478a62

Published CVSS scores

5.5Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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.

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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-20Improper Input Validation
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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