CVE-2026-22858

9.1 CRITICAL
Published: January 14, 2026 Modified: January 20, 2026
View on NVD

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/FreeRDP/FreeRDP/releases/tag/3.20.1
Source: security-advisories@github.com
Release Notes
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-qmqf-m84q-x896
Source: security-advisories@github.com
Vendor Advisory Exploit

2 reference(s) from NVD

Quick Stats

CVSS v3 Score
9.1 / 10.0
EPSS (Exploit Probability)
0.1%
25th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

freerdp