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.
References (2)
Core 2
Core References
Vendor Advisory, Exploit x_refsource_confirm
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-qmqf-m84q-x896
Release Notes x_refsource_misc
https://github.com/FreeRDP/FreeRDP/releases/tag/3.20.1
Scores
CVSS v3
9.1
EPSS
0.0009
EPSS Percentile
25.3%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
CISA SSVC
Vulnrichment
Exploitation
poc
Automatable
no
Technical Impact
partial
Details
CWE
CWE-125
CWE-758
Status
published
Products (1)
freerdp/freerdp
< 3.20.1
Published
Jan 14, 2026
Tracked Since
Feb 18, 2026