CVE-2026-22858 Details
Description
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.20.1, global-buffer-overflow was observed in FreeRDP's Base64 decoding path. The root cause appears to be implementation-defined char signedness: on Arm/AArch64 builds, plain char is treated as unsigned, so the guard c <= 0 can be optimized into a simple c != 0 check. As a result, non-ASCII bytes (e.g., 0x80-0xFF) may bypass the intended range restriction and be used as an index into a global lookup table, causing out-of-bounds access. This vulnerability is fixed in 3.20.1.
A global buffer overflow vulnerability has been identified in FreeRDP, a free implementation of the Remote Desktop Protocol, in versions prior to 3.20.1. The issue arises from the handling of character signedness in Base64 decoding. On Arm/AArch64 builds, characters are treated as unsigned, allowing non-ASCII bytes to bypass range checks and access a global lookup table out of bounds, leading to memory corruption.
Users can upgrade to FreeRDP version 3.20.1, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jan 14, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-125 | Out-of-bounds Read | [email protected] |
| CWE-758 | Reliance on Undefined, Unspecified, or Implementation-Defined Behavior | [email protected] |
| CWE-787 | Out-of-bounds Write | redhat-SADP |
Affected Products
| Product | Versions |
|---|---|
| freerdp freerdp | < 3.20.1 |
CPE
Remediation
| |
Change History
6 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 15, 2026 | CVE Modified | redhat-SADP |
| Jun 30, 2026 | CVE Modified | redhat-SADP |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jan 20, 2026 | Initial Analysis | [email protected] |
| Jan 14, 2026 | New CVE Received | [email protected] |