CVE-2026-56297
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 · uneditedFreeRDP before 3.22.0 contains a use-after-free vulnerability in dvcman_channel_close and dvcman_call_on_receive due to improper synchronization of channel_callback access. A malicious RDP server can trigger a race condition by sending DYNVC_DATA and DYNVC_CLOSE messages concurrently, causing heap-use-after-free in the drdynvc client thread and potentially enabling remote code execution or denial of service.
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 confidenceFreeRDP before 3.22.0 has a race condition vulnerability in the dynamic virtual channel (DYNVC) handling code. A malicious RDP server can send DYNVC_DATA and DYNVC_CLOSE messages concurrently, causing the client to access channel_callback after it has been freed in the dvcman_channel_close or dvcman_call_on_receive functions, resulting in heap use-after-free and potential RCE.
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< 3.22.0CVSS 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
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify FreeRDP installation and versionRun `freerdp-version` or `xfreerdp --version` to display the installed FreeRDP version. On Linux systems, also check via package manager: `dpkg -l | grep freerdp` or `rpm -qa | grep freerdp`.Affected if The installed version is lower than 3.22.0 (e.g., 3.21.0, 3.20.0, 2.x.x, etc.)
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Review FreeRDP client build configurationCheck the build configuration for DVC support: look for ENABLE_DVC or similar build flags in the binary or source configuration files. Run `xfreerdp /help` to see enabled options.Affected if Dynamic virtual channel support is compiled in, which is the standard configuration.
A user is affected if they are running any FreeRDP version prior to 3.22.0 and use the client to connect to RDP servers, as the race condition in DYNVC handling can be triggered by a malicious server sending concurrent DYNVC_DATA and DYNVC_CLOSE messages.
Generated from the published advisory. Verify against your own configuration.
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 · scoped3.22.0
Upgrade FreeRDP to version 3.22.0 or later which contains the fix for proper synchronization of channel_callback access.
FreeRDP 3.22.0 or later
- 1. Identify the current FreeRDP version installed on the system (e.g., via 'freerdp-version', 'xfreerdp --version', or package manager)
- 2. Upgrade FreeRDP to version 3.22.0 or later using the appropriate package manager or build from source
- 3. Verify the upgrade was successful by checking the installed version matches or exceeds 3.22.0
- 4. Test RDP connections to ensure the client functions correctly after the upgrade
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation12.0 h
- Testing10.0 h
- Review / QA6.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,864.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-56297 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-56297 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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