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
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-qmqf-m84q-x896
CVSS impact metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
9.1 · Critical
Information
Source identifier
Vulnerability status
Analyzed
Published
2026-01-14T18:16:43.520Z
6 days agoLast modified
2026-01-20T18:33:32.850Z
9 hours ago