CVE-2026-109255
Received Received - Intake

Integer Truncation in FreeRDP Leads to Heap Buffer Overflow

Publication date: 2026-10-12

Last updated on: 2026-10-12

Assigner: VulnCheck

Description
FreeRDP 3.0.0 before 3.32.0 contains an integer truncation vulnerability in license_check_stream_length that allows a malicious RDP server to trigger a heap buffer overflow on 32-bit clients. Attackers can send a crafted SERVER_LICENSE_REQUEST with a large scopeCount that bypasses length checks, causing out-of-bounds writes leading to denial of service or remote code execution.

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Meta Information

Published
2026-10-12
Last Modified
2026-10-12
Generated
2026-10-12
AI Q&A
2026-10-12
EPSS Evaluated
N/A
NVD
CVE-2026-109255
EUVD
EUVD-2026-97699

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
FreeRDP FreeRDP 3.0.0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-122 A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

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Executive Summary

This vulnerability is an integer truncation flaw in FreeRDP's license_check_stream_length function. On 32-bit clients, a malicious RDP server can send a crafted SERVER_LICENSE_REQUEST with a large scopeCount value. The function incorrectly truncates a 64-bit value to 32 bits, bypassing length checks and causing a heap buffer overflow during license negotiation.

Detection Guidance

To detect this vulnerability, check the FreeRDP version on your system. Run: freerdp2-shadow --version or apt list --installed | grep freerdp. If the version is 3.0.0 through 3.31.0, the system is vulnerable. Monitor network traffic for SERVER_LICENSE_REQUEST packets with unusually large scopeCount values.

Impact Analysis

This flaw can lead to denial of service or remote code execution on affected 32-bit FreeRDP clients. Attackers exploiting this could crash the application or take control of the system by sending specially crafted packets during RDP sessions.

Mitigation Strategies

Upgrade FreeRDP to version 3.32.0 or later immediately. If upgrading is not possible, restrict network access to FreeRDP services or disable RDP server functionality until patched. Monitor for exploitation attempts targeting license negotiation.

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