EUVD-2026-78637
GHSA-fqjp-p646-qwhr
Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/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
Primary rating from Vendor (VulnCheck) · only source for this CVE.
CVSS VectorVendor: VulnCheck
Lifecycle Timeline
3DescriptionCVE.org
FreeRDP before 3.31.0 contains a denial-of-service vulnerability in the URBDRC control-transfer request path that fails to validate OutputBufferSize before forwarding to the libusb backend. A malicious RDP server can send a control-transfer request with OutputBufferSize set to 65536, triggering a reachable assertion that terminates the client process.
AnalysisAI
FreeRDP clients before 3.31.0 terminate unexpectedly when connected to a malicious RDP server, because the URBDRC (USB redirection) control-transfer request path forwards an attacker-supplied OutputBufferSize of 65536 to the libusb backend without validating it, hitting a reachable assertion. The attacker must control the RDP server and convince a user to connect, so exploitation is network-facing but user-initiated. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires three concrete preconditions: (1) the victim's FreeRDP client must have the URBDRC / USB redirection virtual channel enabled and successfully negotiated with the server - if USB redirection is not offered or not loaded, the vulnerable control-transfer path is never reached; (2) the attacker must control or compromise the RDP server the victim connects to (malicious host or man-in-the-middle), since the trigger is an OutputBufferSize value of 65536 sent in a server-to-client control-transfer request; and (3) the client build must retain the reachable assertion in the URBDRC/libsub path, i.e. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 base score of 7.1 (AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N) is driven entirely by high availability impact; there is no confidentiality or integrity impact and no scope change, so this is a pure denial-of-service bug rather than a code-execution primitive. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Upgrade to FreeRDP 3.31.0 or later, which is the first release containing the OutputBufferSize validation fix (per vendor advisory GHSA-w9qg-g24r-77f6 at https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-w9qg-g24r-77f6); Linux distributions should apply the corresponding package update once their maintainers backport the fix. … Detailed patch versions, workarounds, and compensating controls in full report. |
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FreeRDP is a free implementation of the Remote Desktop Protocol. Rated critical severity (CVSS 9.8), this vulnerability
FreeRDP is a free implementation of the Remote Desktop Protocol (RDP), released under the Apache license. Rated critical
FreeRDP is a free implementation of the Remote Desktop Protocol (RDP), released under the Apache license. Rated critical
FreeRDP is a free implementation of the Remote Desktop Protocol (RDP), released under the Apache license. Rated critical
Same weakness CWE-617 – Reachable Assertion
View allSame technique Denial Of Service
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External POC / Exploit Code
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