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CWE-290Weakness · CWE-290

CVE-2026-39959

HIGH · 7.1 CVSS v3.1 Published 2026-04-09
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
73/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Tmds.DBus provides .NET libraries for working with D-Bus from .NET. Tmds.DBus and Tmds.DBus.Protocol are vulnerable to malicious D-Bus peers. A peer on the same bus can spoof signals by impersonating the owner of a well-known name, exhaust system resources or cause file descriptor spillover by sending messages with an excessive number of Unix file descriptors, and crash the application by sending malformed message bodies that cause unhandled exceptions on the SynchronizationContext. This vulnerability is fixed in Tmds.DBus 0.92.0 and Tmds.DBus.Protocol 0.92.0 and 0.21.3.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Tmds.DBus and Tmds.DBus.Protocol libraries for .NET D-Bus communication contain multiple vulnerabilities exploitable by malicious peers on the same bus: signal spoofing via well-known name impersonation, resource exhaustion from excessive Unix file descriptor messages, and application crashes from unhandled exceptions caused by malformed message bodies on the SynchronizationContext.

MitigationUpgrade Tmds.DBus to version 0.92.0 or Tmds.DBus.Protocol to version 0.92.0 or 0.21.3 to obtain the security patches.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify if Tmds.DBus packages are used
    Search project files (*.csproj, *.fsproj), packages.config, or *.deps.json for 'Tmds.DBus' package references. In .NET projects, run 'dotnet list package' in the project directory.
    Affected if No Tmds.DBus or Tmds.DBus.Protocol package reference is found - the application is not using the affected libraries.
  2. Determine installed version of Tmds.DBus
    For NuGet: check the version in the package reference (e.g., <PackageReference Include="Tmds.DBus" Version="x.y.z" />). Or run 'dotnet list package' to see installed versions.
    Affected if The installed version is lower than 0.92.0 (e.g., 0.91.x, 0.90.x, etc.) - the version is vulnerable.
  3. Determine installed version of Tmds.DBus.Protocol
    Check for 'Tmds.DBus.Protocol' package reference in project files or run 'dotnet list package'. Note both libraries may be present.
    Affected if The installed version is lower than 0.21.3, or between 0.21.3 and 0.92.0 (excluding both) - the version is vulnerable.
  4. Confirm D-Bus usage in the application
    Search source code for 'DBusConnection', 'DBusClient', or 'Tmds.DBus' namespace usage. Look for D-Bus bus names, object paths, or interface usage in the codebase.
    Affected if The code does not actually instantiate D-Bus connections - the vulnerabilities require an active D-Bus connection to be exploitable.

You are affected if your project uses Tmds.DBus versions below 0.92.0 or Tmds.DBus.Protocol versions below 0.21.3 (or between 0.21.3 and 0.92.0), and your application connects to a D-Bus where malicious peers could send spoofed signals, excessive file descriptors, or malformed messages.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Tmds.DBus to version 0.92.0 or Tmds.DBus.Protocol to version 0.92.0 or 0.21.3 to obtain the security patches.

Recommended fix High confidence

Tmds.DBus 0.92.0 or later; Tmds.DBus.Protocol 0.92.0 (or 0.21.3) or later

  1. Identify the currently installed Tmds.DBus and Tmds.DBus.Protocol packages in your project by examining your .csproj file, packages.config, or by running 'dotnet list package'
  2. For Tmds.DBus: Update the package reference to version 0.92.0 or later by running 'dotnet add package Tmds.DBus --version 0.92.0'
  3. For Tmds.DBus.Protocol: Update the package reference to version 0.92.0 or later (or 0.21.3 for a lower minor version) by running 'dotnet add package Tmds.DBus.Protocol --version 0.92.0' or 'dotnet add package Tmds.DBus.Protocol --version 0.21.3'
  4. Rebuild and test your application to verify the upgrade does not break existing functionality
Caveat Check the release notes at the project GitHub repository for any breaking changes between your current version and 0.92.0

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,720
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-39959 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data