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Freerdp CVE-2026-22858

CRITICAL
Out-of-bounds Read (CWE-125)
2026-01-14 security-advisories@github.com
9.1
CVSS 3.1 · GitHub Advisory
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Severity by source

GitHub Advisory PRIMARY
9.1 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
SUSE
CRITICAL
qualitative
Red Hat
7.4 HIGH
qualitative

Primary rating from GitHub Advisory.

CVSS VectorGitHub Advisory

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

Lifecycle Timeline

4
Patch released
Apr 09, 2026 - 20:30 nvd
Patch available
Analysis Generated
Mar 12, 2026 - 21:54 vuln.today
PoC Detected
Jan 20, 2026 - 18:33 vuln.today
Public exploit code
CVE Published
Jan 14, 2026 - 18:16 nvd
CRITICAL 9.1

DescriptionGitHub Advisory

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.

AnalysisAI

FreeRDP Base64 decoder has a global buffer overflow on ARM builds due to implementation-defined char signedness. Fixed in 3.20.1.

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access
Send RDP connection with malicious Base64 data
Exploit
Trigger char signedness vulnerability in decoder
Execution
Access out-of-bounds global buffer
Impact
Crash or leak sensitive memory

Vulnerability AssessmentAI

Exploitation FreeRDP versions prior to 3.20.1 compiled on Arm/AArch64 architectures where plain char is unsigned. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment CVSS 9.1 (Critical). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario A malicious RDP server sends Base64 data with non-ASCII bytes that trigger the overflow on ARM FreeRDP clients.
Remediation Update to 3.20.1. Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

Within 24 hours: Identify all affected systems and apply vendor patches immediately. …

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Threat intelligence, references, and detailed analysis are available after sign-in.

Vendor StatusVendor

SUSE

Severity: Critical
Product Status
Container suse/sl-micro/6.0/baremetal-os-container:latest Container suse/sl-micro/6.0/kvm-os-container:latest Container suse/sl-micro/6.0/rt-os-container:latest Affected
Container suse/sl-micro/6.0/base-os-container:latest Container suse/sl-micro/6.0/toolbox:latest Image SL-Micro Image SLE-Micro Image SLE-Micro-Azure Image SLE-Micro-BYOS Image SLE-Micro-BYOS-Azure Image SLE-Micro-BYOS-EC2 Image SLE-Micro-BYOS-GCE Image SLE-Micro-EC2 Image SLE-Micro-GCE Affected
Container suse/sl-micro/6.1/baremetal-os-container:2.2.1-7.43 Container suse/sl-micro/6.1/kvm-os-container:2.2.1-5.67 Container suse/sl-micro/6.1/rt-os-container:2.2.1-5.57 Affected
Container suse/sl-micro/6.1/base-os-container:2.2.1-5.64 Image SL-Micro-Azure Image SL-Micro-BYOS-Azure Image SL-Micro-BYOS-EC2 Image SL-Micro-BYOS-GCE Image SL-Micro-EC2 Image SUSE-Multi-Linux-Manager-Proxy-BYOS-Azure Image SUSE-Multi-Linux-Manager-Proxy-BYOS-EC2 Image SUSE-Multi-Linux-Manager-Proxy-BYOS-GCE Image SUSE-Multi-Linux-Manager-Server-Azure-llc Image SUSE-Multi-Linux-Manager-Server-Azure-ltd Image SUSE-Multi-Linux-Manager-Server-BYOS-Azure Image SUSE-Multi-Linux-Manager-Server-BYOS-EC2 Image SUSE-Multi-Linux-Manager-Server-BYOS-GCE Image SUSE-Multi-Linux-Manager-Server-EC2-llc Image SUSE-Multi-Linux-Manager-Server-EC2-ltd Affected
SUSE Liberty Linux 8 Fixed

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CVE-2026-22858 vulnerability details – vuln.today

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