CVE-2026-22858

CRITICAL

9.1

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.

CVE Details

CVSS v3.1 Score9.1

SeverityCRITICAL

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published1/14/2026

Last Modified1/20/2026

Sourcenvd

Honeypot Sightings0

Affected Products

freerdp:freerdp

Weaknesses (CWE)

CWE-125CWE-758

References

https://github.com/FreeRDP/FreeRDP/releases/tag/3.20.1(security-advisories@github.com)

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-qmqf-m84q-x896(security-advisories@github.com)

IOC Correlations

No correlations recorded

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