CVE-2026-39959

Signal spoofing and service interruption via peer messages

Published Apr 9, 2026 · Updated Apr 9, 2026

Input validation flaws in Tmds.DBus and Tmds.DBus.Protocol allow local users on the same D-Bus to spoof signals or crash applications. Signal matching failed to verify ownership of claimed well-known names, message parsing accepted more than 16 Unix file descriptors and spilled extras into the next message, and signal handlers let malformed-body exceptions reach the SynchronizationContext. Access to the same D-Bus is required; consequences are limited to forged signals, file-descriptor exhaustion or spillover, and process crashes.

CVSS severity7.1
High
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Input validation flaws in Tmds.DBus and Tmds.DBus.Protocol allow local users on the same D-Bus to spoof signals or crash applications. Signal matching failed to verify ownership of claimed well-known names, message parsing accepted more than 16 Unix file descriptors and spilled extras into the next message, and signal handlers let malformed-body exceptions reach the SynchronizationContext. Access to the same D-Bus is required; consequences are limited to forged signals, file-descriptor exhaustion or spillover, and process crashes.

The record

CVE
CVE-2026-39959
Published
Apr 9, 2026
Updated
Apr 9, 2026
Vendor
tmds
Product
Tmds.DBus
Classifications
CWE-290, CWE-770, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 9, 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=< 0.92.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

tmds · Tmds.DBusversion=< 0.92.0
tmds · Tmds.DBus.Protocolversion=< 0.21.3; version=>= 0.22.0, < 0.92.0

Published CVSS scores

7.1GitHub, Inc.CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/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-290Authentication Bypass by Spoofing
CWE-770Allocation of Resources Without Limits or Throttling
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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