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FreeRDP EUVDEUVD-2026-51860

| CVE-2026-67293 CRITICAL
Improper Certificate Validation (CWE-295)
2026-08-01 VulnCheck GHSA-wc6m-wggm-hjr8
Information Disclosure OpenSSL Freerdp
Critical
Disputed · 9.3 Vendor: VulnCheck
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Severity by source

Sources disagree (Medium–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
6.8 MEDIUM

MITM position plus a valid parent-domain wildcard cert makes AC:H; victim must initiate the connection (UI:R); impact is session confidentiality/integrity, not availability, so A:N.

3.1 AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
4.0 AV:N/AC:H/AT:P/PR:N/UI:P/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
4.2 MEDIUM
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 - 13:02 vuln.today
Analysis Generated
Aug 01, 2026 - 13:02 vuln.today
CVE Published
Aug 01, 2026 - 12:22 cve.org
CRITICAL 9.3

DescriptionCVE.org

FreeRDP before 3.29.0 (affected versions <= 3.28.0) contains an improper certificate hostname validation vulnerability. The TLS hostname matcher (tls_match_hostname() in libfreerdp/crypto/tls.c) treats a wildcard pattern such as *.example.com as matching any hostname ending in .example.com, so it incorrectly accepts a wildcard certificate for multi-label subdomains like a.b.example.com (which OpenSSL's X509_check_host() rejects). This weakens TLS server authentication under wildcard-certificate conditions.

Articles & Coverage 1

News Critical TLS Auth Bypass in FreeRDP RDP Client <=3.28.0 - CVE-2026-67293 Aug 01, 2026

AnalysisAI

TLS server-authentication bypass in FreeRDP RDP client versions 3.28.0 and earlier lets a man-in-the-middle present a wildcard certificate (*.example.com) that is wrongly accepted for multi-label subdomains such as a.b.example.com. The flaw lives in tls_match_hostname() in libfreerdp/crypto/tls.c, which treats a wildcard as matching any hostname ending in the parent domain - behavior stricter OpenSSL X509_check_host() rejects. Reported by VulnCheck with a vendor patch available; no public exploit identified at time of analysis.

Technical ContextAI

FreeRDP is a widely used open-source implementation of the Microsoft Remote Desktop Protocol (RDP), embedded in clients like Remmina, GNOME Connections, Weston, and many thin-client/VDI stacks. The defect is a CWE-295 (Improper Certificate Validation) issue in FreeRDP's home-grown TLS hostname matcher. RFC 6125 and OpenSSL semantics restrict a wildcard label to matching exactly one DNS label (so *.example.com matches host.example.com but NOT a.b.example.com). FreeRDP's tls_match_hostname() instead performs a permissive suffix comparison, accepting any hostname ending in .example.com. Because the check runs when the RDP client validates the server's TLS certificate during connection setup, an attacker holding a legitimate wildcard certificate for a parent domain can impersonate arbitrarily deep subdomains within that domain.

RemediationAI

Upgrade to FreeRDP 3.29.0 or later, which corrects the wildcard-matching logic in tls_match_hostname() (Vendor-released patch: 3.29.0; fix commit f3b4347105114fe7453828736bea069999af319f, advisory GHSA-5wr6-8m8j-3h7f). Distribution users should apply their packaged update once it incorporates the fix. Where immediate patching is not possible, compensating controls include pinning the expected server certificate or connecting only over trusted network paths (VPN/IPsec) to remove the MITM prerequisite, and avoiding reliance on broad wildcard certificates for RDP endpoints in favor of exact-hostname certificates - the trade-off is added certificate-management overhead and the loss of wildcard convenience. Restricting RDP connections to known, statically-routed hosts further limits an attacker's ability to interpose.

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Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise Module for Package Hub 15 SP7 Affected
SUSE Linux Enterprise Module for Package Hub 15 SP7 Affected
SUSE Linux Enterprise Server 15 SP7 Affected

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EUVD-2026-51860 vulnerability details – vuln.today
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