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highAuth Bypass

CVE-2026-72746

CVE-2026-72746 — FreeRDP before 3.30.0 RDSTLS Server Authentication Bypass via PDU-type Confusion

FreeRDP before 3.30.0 contains a server-side authentication bypass in the RDSTLS handshake. When a server is configured with RdstlsSecurity = TRUE, the handshake dispatches inbound PDUs based solely on the attacker-supplied wire pduType without verifying that the received PDU is the one required at the current step. Because the rdpRdstls object is calloc-zeroed, its resultCode defaults to 0 (RDSTLS_RESULT_SUCCESS). An unauthenticated remote client can send a Capabilities PDU instead of the required Authentication Request PDU; rdstls_process_capabilities() returns success without ever setting resultCode, so the server responds with an AUTHRSP carrying resultCode SUCCESS and treats the session as authenticated without evaluating any password, redirection GUID, or auto-reconnect cookie. This affects the released FreeRDP 3.x series (e.g., 3.27.1) and master HEAD; at the time of the advisory no patched version was available.

Published Updated Sources: NVD, FreeRDP (CNA), GitHub, SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

0%

ahead of 0% of scored CVEs

Affects

FreeRDP

FreeRDP

CVSS base

7.5

high · 2 sources

Remediation

The vendor's own words where we have them.

Upgrade FreeRDP to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

  • Identify exposed assets running affected vendor/product/version combinations.
  • Prioritize based on EPSS, PoC availability, and external exposure.
  • Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

VendorProductVersionsStatus
FreeRDPFreeRDP3.0.0 to < 3.30.0Vulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

None

Confidentiality

High

Integrity

None

Scope

Unchanged

Attack Complexity

Low

Attack Vector

Network

Privileges Req

None

User Interaction

None

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactSource
7.5CVSS 3.1high3.93.6NVD, FreeRDP (CNA)
8.7CVSS 4.0highFreeRDP (CNA)

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

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-287 · Improper Authentication

  • Read Application Data
  • Gain Privileges or Assume Identity
  • Execute Unauthorized Code or Commands

Mitigation: Use an authentication framework or library such as the OWASP ESAPI Authentication feature.::

Weakness & attack patterns

  • CWE-287Improper Authentication

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

CAPEC-114 · Authentication AbuseCAPEC-115 · Authentication BypassCAPEC-151 · Identity SpoofingCAPEC-194 · Fake the Source of DataCAPEC-22 · Exploiting Trust in ClientCAPEC-57 · Utilizing REST's Trust in the System Resource to Obtain Sensitive DataCAPEC-593 · Session HijackingCAPEC-633 · Token ImpersonationCAPEC-650 · Upload a Web Shell to a Web ServerCAPEC-94 · Man in the Middle Attack
  • T1548Abuse Elevation Control Mechanism
  • T1040Network Sniffing
  • T1185Browser Session Hijacking

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

  • Prioritize edge telemetry for network-reachable FreeRDP.
web/proxy/WAF logsapplication logsnetwork IDS/IPSidentity provider logsauthentication audit logs

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

  1. 2026
  2. Added · CVSS 3.1 7.5 (AV:N)

    Aug 11, 2026 · NVD

  3. Initial · CVE published

    Aug 11, 2026 · NVD

References

3 on the record

Elsewhere on this site

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record1

What should defenders know first?

CVE-2026-72746 is FreeRDP before 3.30.0 RDSTLS Server Authentication Bypass via PDU-type Confusion, a high vulnerability affecting FreeRDP from FreeRDP. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-72746. Public exploit evidence is: A public PoC is not confirmed from current sources for CVE-2026-72746. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 7.5 describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.