CVE•Published 2026-01-14•Modified 2026-06-30•1 article on news•6 live references•NVD data

CVE-2026-22858Freerdp · Freerdp

Vulnerability data via NVD (ingested)

CVSS v3.1

9.1

CRITICAL

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

EPSS percentile

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Weaknesses (CWE)

CWE-125Out-of-bounds Read CWE-758Reliance on Undefined, Unspecified, or Implementation-Defined Behavior CWE-787Out-of-bounds Write

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.

Timeline

Published 2026-01-14

Modified 2026-06-30

External references

NVD MITRE Exploit-DB Sploitus trickest/cve VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag0 hosts

vuln:CVE-2026-22858

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product

product:"Freerdp Freerdp"

All exposed Freerdp Freerdp instances — cross-reference with the CVE's affected-version range.

Shodan · banner/body mention

http.html:"Freerdp"

HTTP body or banner mentions "Freerdp" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2026-22858