CVE-2026-29776 in FreeRDP
Summary
by MITRE • 03/13/2026
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0, Integer Underflow in update_read_cache_bitmap_order Function of FreeRDP's Core Library This vulnerability is fixed in 3.24.0.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 05/13/2026
The vulnerability identified as CVE-2026-29776 affects FreeRDP, an open-source implementation of the Remote Desktop Protocol that enables remote desktop connections across various platforms. This issue resides within the core library of FreeRDP and specifically impacts the update_read_cache_bitmap_order function, which handles bitmap caching operations during remote desktop sessions. The vulnerability represents a critical security flaw that could potentially allow attackers to disrupt service availability or execute arbitrary code within the context of the affected system.
The technical flaw manifests as an integer underflow condition within the update_read_cache_bitmap_order function, where the software fails to properly validate input parameters before performing arithmetic operations. When processing bitmap cache orders, the function attempts to subtract values that may result in negative integers, causing the unsigned integer to wrap around to a large positive value. This condition creates a scenario where memory allocation or buffer operations could be manipulated to access invalid memory locations or bypass security checks. The vulnerability is classified under CWE-191, which specifically addresses integer underflow conditions that can lead to unexpected behavior in software systems.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it could potentially enable remote code execution or privilege escalation depending on the specific implementation details and system configuration. Attackers could exploit this condition by crafting malicious bitmap cache orders that trigger the integer underflow, potentially leading to memory corruption or arbitrary code execution. The vulnerability affects all FreeRDP versions prior to 3.24.0, making it a significant concern for organizations that rely on remote desktop connectivity for their operations. This issue aligns with ATT&CK technique T1210, which covers exploitation of remote services through manipulation of data structures, and represents a classic example of how integer arithmetic errors can lead to security breaches.
Organizations utilizing FreeRDP should immediately upgrade to version 3.24.0 or later to remediate this vulnerability. The fix implemented in version 3.24.0 includes proper input validation and bounds checking within the update_read_cache_bitmap_order function to prevent the integer underflow condition from occurring. System administrators should also implement network segmentation and access controls to limit exposure, while monitoring for suspicious network traffic patterns that might indicate exploitation attempts. Additionally, organizations should consider implementing automated patch management solutions to ensure timely deployment of security updates across all remote desktop implementations. The vulnerability demonstrates the importance of rigorous input validation and proper integer handling in security-critical code, particularly within protocols that handle untrusted data from remote sources.