CVE-2026-39959 Tmds.DBus: malicious D-Bus peers can spoof signals, exhaust file descriptor resources, and cause denial of service
Malicious D-Bus peers can spoof signals, exhaust file descriptors, and crash applications via malformed messages in Tmds.DBus libraries.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-39959?
CVE-2026-39959 is a high-severity denial of service vulnerability in Tmds.DBus, published on 9 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-39959?
6 open source packages ship an affected version, including Tmds.DBus.Protocol and Tmds.DBus.
| Package | Affected | Fixed in |
|---|---|---|
Tmds.DBus.Protocol NuGet | All versions | 0.21.3 |
Tmds.DBus.Protocol NuGet | All versions | 0.21.3 |
Tmds.DBus.Protocol NuGet | From 0.22.0 | 0.92.0 |
Tmds.DBus.Protocol NuGet | From 0.22.0 | 0.92.0 |
Tmds.DBus NuGet | All versions | 0.92.0 |
Tmds.DBus NuGet | All versions | 0.92.0 |
How do I fix CVE-2026-39959?
Upgrade Tmds.DBus.Protocol to a fixed version for your release line: 0.21.3 or 0.92.0.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-39959 being exploited?
There is no known exploitation of CVE-2026-39959 in the wild and no public exploit code.
Sources
Also known as GHSA-xrw6-gwf8-vvr9.