CVE-2026-56297Public exploitNetwork attack vector

Client crash via DRDYNVC callback race

Published Jul 8, 2026 · Updated Jul 8, 2026

Use-after-free in FreeRDP before 3.22.0 allows remote attackers controlling an RDP server to crash connected clients via DYNVC messages. Within channels/drdynvc/client/drdynvc_main.c, dvcman_channel_close calls OnClose before clearing channel_callback, while dvcman_call_on_receive reads the freed callback without synchronization. Exploitation requires a client connection to an attacker-controlled or compromised RDP server; the demonstrated outcome is a client crash, while code execution is not demonstrated.

CVSS severity8.3
High
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in FreeRDP before 3.22.0 allows remote attackers controlling an RDP server to crash connected clients via DYNVC messages. Within channels/drdynvc/client/drdynvc_main.c, dvcman_channel_close calls OnClose before clearing channel_callback, while dvcman_call_on_receive reads the freed callback without synchronization. Exploitation requires a client connection to an attacker-controlled or compromised RDP server; the demonstrated outcome is a client crash, while code execution is not demonstrated.

The record

CVE
CVE-2026-56297
Published
Jul 8, 2026
Updated
Jul 8, 2026
Vendor
FreeRDP
Product
FreeRDP
Classifications
CWE-362, CWE-416, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <3.22.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FreeRDP · FreeRDPversion=0 <3.22.0

Published CVSS scores

8.1NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
7.0VulnCheckCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H
8.3VulnCheckCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CWE-416Use After Free
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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