# CVE-2026-121962: FreeRDP heap buffer overflow in transport_default_read_pdu

Source: https://junglewise.ai/threats/cve-2026-121962-freerdp-before-3-32-2-contains-a-heap-buffer-overflow-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-04. Updated: 2026-11-04  
License: CC BY 4.0 with a link back

CVE-2026-121962 · Severity: high · CVSS 8.1 · Published 2026-11-04

FreeRDP is an open-source remote desktop client that connects to Windows RDP servers. A malicious RDP server can exploit a buffer overflow vulnerability by sending fragmented Early User Authorization responses, allowing it to crash the client or potentially execute code on the attacker's terms.

Technologies: [FreeRDP Project FreeRDP](https://junglewise.ai/threats/technologies/freerdp-project-freerdp). Vendors: [FreeRDP Project](https://junglewise.ai/threats/vendors/freerdp-project).

## Quick answers

**Is CVE-2026-121962 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-121962 being exploited in the wild.

**How severe is CVE-2026-121962?** High severity, with a CVSS score of 8.1, published 4 November 2026.

**Which products and versions are affected?** FreeRDP Project FreeRDP before 3.32.2.

**Is there a fix for CVE-2026-121962?** Yes: fixed in 3.32.2. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-121962 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-121962?** Check whether you run FreeRDP Project FreeRDP at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 3.32.2

## Technical details

A heap buffer overflow exists in the transport_default_read_pdu function when handling partial Early User Authorization (EUA) reads during PROTOCOL_HYBRID_EX CredSSP negotiation. The vulnerable code checks total stream capacity rather than remaining space at the current pointer position, allowing an attacker to advance the write pointer beyond a 16 KiB allocation through repeated short reads. This results in out-of-bounds heap writes that cause denial of service and potentially memory corruption.

## Affected products

- FreeRDP Project FreeRDP before 3.32.2

## Timeline

- 2026-10-20: disclosed
- 2026-11-04: advisory

## References

- [https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-j536-qc58-pmf8](https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-j536-qc58-pmf8)
- [https://www.vulncheck.com/advisories/freerdp-before-3.32.2-heap-buffer-overflow-via-early-user-authorization-read](https://www.vulncheck.com/advisories/freerdp-before-3.32.2-heap-buffer-overflow-via-early-user-authorization-read)

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- [FreeRDP NULL pointer dereference in RDPGFX ResetGraphics](https://junglewise.ai/threats/cve-2026-121402-freerdp-before-3-32-2-contains-a-null-pointer-dereference)
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