Integer Underflow Affecting freerdp3 package, versions <3.30.0+dfsg-0ubuntu0.24.04.1


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.38% (31st percentile)

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  • Snyk IDSNYK-UBUNTU2404-FREERDP3-18519824
  • published18 Aug 2026
  • disclosed1 Aug 2026

Introduced: 1 Aug 2026

NewCVE-2026-67298  (opens in a new tab)
CWE-191  (opens in a new tab)

How to fix?

Upgrade Ubuntu:24.04 freerdp3 to version 3.30.0+dfsg-0ubuntu0.24.04.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream freerdp3 package and not the freerdp3 package as distributed by Ubuntu. See How to fix? for Ubuntu:24.04 relevant fixed versions and status.

FreeRDP versions 3.28.0 and earlier contain a heap buffer overflow in the server-side RAIL channel handler (rail_server_handle_messages() in channels/rail/server/rail_main.c). When processing a RAIL PDU header, the code subtracts RAIL_PDU_HEADER_LENGTH from the peer-controlled orderLength field without first verifying orderLength is at least the header length. For orderLength values 0..3 this causes an unsigned integer underflow to a very large size, which bypasses the Stream_EnsureRemainingCapacity() capacity check (due to pointer arithmetic wraparound) and is then passed to WTSVirtualChannelRead(), resulting in an out-of-bounds heap write. A malicious or compromised RDP client can exploit this to corrupt the heap and crash the server. Fixed in FreeRDP 3.29.0.

CVSS Base Scores

version 3.1