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FreeRDP CVE-2026-67294

| EUVDEUVD-2026-51842 CRITICAL
Improper Certificate Validation (CWE-295)
2026-08-01 VulnCheck GHSA-v6mf-3jqv-cgr7
Authentication Bypass Freerdp
Critical
Disputed · 9.3 Vendor: VulnCheck
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Severity by source

Sources disagree (Low–Critical)
Vendor (VulnCheck) PRIMARY
9.3 CRITICAL
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
vuln.today AI
7.4 HIGH

Requires a MITM position and a trusted-CA clientAuth certificate in an EKU-separated environment (AC:H); server impersonation compromises session confidentiality and integrity but not availability directly.

3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
4.0 AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
SUSE
4.8 MEDIUM
AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Red Hat
3.7 LOW
qualitative

vuln.today treats the vendor’s rating as authoritative. A higher third-party CVSS (e.g. CISA-ADP) is shown for transparency but does not drive the headline severity.

CVSS VectorVendor: VulnCheck

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
X

Lifecycle Timeline

3
Source Code Evidence Fetched
Aug 01, 2026 - 13:03 vuln.today
Analysis Generated
Aug 01, 2026 - 13:03 vuln.today
CVE Published
Aug 01, 2026 - 12:22 cve.org
CRITICAL 9.3

DescriptionCVE.org

FreeRDP before 3.29.0 improperly validates the Extended Key Usage (EKU) purpose of the peer certificate during client-side server TLS authentication. In x509_utils_verify(), when server-purpose (X509_PURPOSE_SSL_SERVER) verification fails, the code falls back to client-purpose and any-purpose verification, so a trusted, hostname-matching certificate valid only for clientAuth can be accepted as the RDP server certificate. In environments relying on EKU separation between client and server certificates, this allows a clientAuth-only certificate issued by a trusted CA to bypass server certificate purpose validation.

AnalysisAI

TLS server certificate purpose validation bypass in FreeRDP before 3.29.0 allows a trusted, hostname-matching certificate issued only for client authentication (clientAuth EKU) to be accepted as a valid RDP server certificate. This weakens the trust model in environments that rely on Extended Key Usage separation between client and server certificates, enabling an attacker who can present such a certificate to impersonate the RDP server. Reported by VulnCheck with a vendor patch available; no public exploit identified at time of analysis and not listed in CISA KEV.

Technical ContextAI

FreeRDP is a widely used open-source implementation of the Remote Desktop Protocol, providing both client and server components and used as the RDP engine behind tools such as Remmina and many Linux/embedded remote desktop clients. The flaw lives in x509_utils_verify(), the routine that validates the peer (server) certificate during client-side server TLS authentication. When the code performs OpenSSL certificate verification with the server purpose set (X509_PURPOSE_SSL_SERVER) and that check fails, it incorrectly falls back to client-purpose and any-purpose verification. The root cause is CWE-295 (Improper Certificate Validation): the EKU/purpose constraint that should distinguish a legitimate serverAuth certificate from a clientAuth-only certificate is not enforced, so a certificate valid only for clientAuth-but issued by a trusted CA and matching the hostname-is treated as an acceptable server certificate. The affected CPE is cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:* for all versions prior to 3.29.0.

RemediationAI

Upgrade FreeRDP to version 3.29.0 or later, which is the vendor-fixed release addressing the EKU purpose-validation fallback (Patch available per vendor advisory; the exact fix commit should be confirmed against GHSA-89c6-jjrw-96h4 because the supplied commit f3b4347 diff does not correspond to certificate code). Consult the advisory at https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-89c6-jjrw-96h4 and the VulnCheck writeup for authoritative fix details. Until upgrading, reduce reliance on EKU separation as the sole trust boundary: pin the expected RDP server certificate or its issuing CA to a dedicated serverAuth-only CA so that clientAuth certificates cannot chain to a trusted anchor, and restrict RDP client connections to known, network-segmented server endpoints to limit machine-in-the-middle opportunities-noting that certificate pinning increases operational overhead when servers rotate certificates.

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Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise Desktop 15 SP7 Not-Affected
SUSE Linux Enterprise Module for Package Hub 15 SP7 Not-Affected
SUSE Linux Enterprise Module for Package Hub 15 SP7 Not-Affected
SUSE Linux Enterprise Server 15 SP7 Affected

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CVE-2026-67294 vulnerability details – vuln.today
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