dbcve.org
FedoraOperating system · Fedoraproject

CVE-2021-41159

HIGH · 8.8 CVSS v3.1 Published 2021-10-21
Fix available
A fix is available. Upgrade to 2.4.1 or later.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
FreeRDP is a free implementation of the Remote Desktop Protocol (RDP), released under the Apache license. All FreeRDP clients prior to version 2.4.1 using gateway connections (`/gt:rpc`) fail to validate input data. A malicious gateway might allow client memory to be written out of bounds. This issue has been resolved in version 2.4.1. If you are unable to update then use `/gt:http` rather than /gt:rdp connections if possible or use a direct connection without a gateway.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

FreeRDP clients prior to version 2.4.1 fail to validate input data when using gateway connections with the RPC transport (/gt:rpc). A malicious gateway can exploit this to write client memory out of bounds, leading to potential memory corruption and arbitrary code execution.

MitigationUpdate FreeRDP to version 2.4.1 or later. If immediate updating is not possible, use /gt:http instead of /gt:rpc for gateway connections, or bypass the gateway entirely with a direct connection.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FedoraOperating system
Affected:= 35
FreerdpApplication
Affected:< 2.4.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed FreeRDP version
    Run 'xfreerdp --version' or 'freerdp --version' from the command line, or query your package manager (e.g., 'rpm -q freerdp' on Fedora/RHEL, 'dpkg -l freerdp' on Debian/Ubuntu)
    Affected if The version returned is less than 2.4.1 or not shown (indicating an older unpatched build)
  2. Locate FreeRDP connection commands or configs
    Search for saved RDP connection files (commonly .rdp files in ~/.config/freerdp/ or user home directories) or check shell history for freerdp/xfreerdp commands
    Affected if You find .rdp configuration files or saved connection commands that specify /gt:rpc or GatewayTransport:=RPC
  3. Check active gateway connections
    Review any scripts, automation, or documentation that launch FreeRDP with the /gt:rpc gateway transport flag (for example: 'xfreerdp /v:server /g:gateway /gt:rpc ...')
    Affected if The gateway transport is explicitly set to RPC (/gt:rpc) in any connection configuration or command line
  4. Verify client is exposed to gateway
    Confirm whether the FreeRDP client is routinely used to connect through Remote Desktop Gateway (RD Gateway) using the RPC transport
    Affected if You connect through a Remote Desktop Gateway using /gt:rpc and the gateway could be controlled by an untrusted party

You are affected if FreeRDP version is below 2.4.1 AND you use /gt:rpc gateway transport connections; without the RPC gateway transport, this specific flaw does not apply.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2.4.1 or later
Fixed in 2.4.1
Interim mitigation

Update FreeRDP to version 2.4.1 or later. If immediate updating is not possible, use /gt:http instead of /gt:rpc for gateway connections, or bypass the gateway entirely with a direct connection.

Recommended fix High confidence

FreeRDP 2.4.1 or later

  1. Upgrade FreeRDP to version 2.4.1 or later to remediate the out-of-bounds write vulnerability
  2. Alternatively, if upgrading is not possible, configure the client to use /gt:http gateway type instead of /gt:rpc, or use a direct connection without a gateway
Caveat Patch release with bug fixes; minimal risk expected but test in non-production environment first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Fedora Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.

Scan for this in your stack

Free · runs locally
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-41159 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data