CVE-2024-26861

Service interruption via concurrent receive-counter access

Published Apr 17, 2024 · Updated May 23, 2026

Race condition in the Linux kernel WireGuard receive path allows local users to interrupt service through concurrent counter access. The decrypt worker reads keypair->receiving_counter.counter while the receive poll path writes it without READ_ONCE() and WRITE_ONCE() annotations, so KCSAN reports a cross-CPU data race. Low-privileged local access and an active WireGuard receive path are required; published evidence limits the reported consequence to availability.

CVSS severity5.5
Medium
EPSS probability0.18%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in the Linux kernel WireGuard receive path allows local users to interrupt service through concurrent counter access. The decrypt worker reads keypair->receiving_counter.counter while the receive poll path writes it without READ_ONCE() and WRITE_ONCE() annotations, so KCSAN reports a cross-CPU data race. Low-privileged local access and an active WireGuard receive path are required; published evidence limits the reported consequence to availability.

The record

CVE
CVE-2024-26861
Published
Apr 17, 2024
Updated
May 23, 2026
Vendor
Siemens
Product
SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
Classifications
CWE-362, CWE-20, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 17, 2024CVE publishedPublication date reported by the CVE source.
  2. May 23, 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=4a7939808afdc57ecaeb72d049e2985321a1e44e; version=5.6.16 <5.7; version=5.7; version=a9e90d9931f3a474f04bab782ccd9d77904941e9 <3f94da807fe1668b9830f0eefbbf7e887b0a7bc6; version=a9e90d9931f3a474f04bab782ccd9d77904941e9 <45a83b220c83e3c326513269afbf69ae6fc65cce; version=a9e90d9931f3a474f04bab782ccd9d77904941e9 <78739d72f16b2d7d549f713f1dfebd678d32484b; version=a9e90d9931f3a474f04bab782ccd9d77904941e9 <bba045dc4d996d03dce6fe45726e78a1a1f6d4c3; version=a9e90d9931f3a474f04bab782ccd9d77904941e9 <d691be84ab898cf136a35176eaf2f8fc116563f0; version=a9e90d9931f3a474f04bab782ccd9d77904941e9 <f87884e0dffd61b47e58bc6e1e2f6843c212b0cc; version=a9e90d9931f3a474f04bab782ccd9d77904941e9 <fdf16de078a97bf14bb8ee2b8d47cc3d3ead09ed

Published CVSS scores

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 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CWE-20Improper Input Validation
T1499.004Application or System Exploitation

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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