Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessLure victim to malicious RDP server
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DeliveryClient connects with serial redirection enabled
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ExploitSend out-of-lifecycle IRP_MJ_READ/WRITE
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ExecutionNull serial handle dereferenced in CommReadFile/CommWriteFile
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ImpactFreeRDP client process crashes
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A10:2025 - Mishandling of Exceptional Conditions
ASVS 5.0
V16 - Security Logging and Error Handling Null pointer safety, defensive checks
MITRE ATT&CK
1 technique across 1 tactic: Impact The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | The victim's FreeRDP client (versions 2.0.0 up to but not including 3.32.0) must have serial-port device redirection enabled over the RDP serial channel on Linux - the vulnerable CommReadFile/CommWriteFile paths are only reached in that configuration. The user must also actively initiate a connection to an attacker-controlled or compromised RDP server (CVSS UI:P / passive interaction), which must then send an IRP_MJ_READ or IRP_MJ_WRITE before the channel's create or after its close. Limiting factors: serial redirection is a non-default, relatively uncommon deployment mode; the attack requires luring the victim to a malicious server rather than attacking a listening service; and impact is limited to a client crash with no code execution or data disclosure. |
| Impact | This is a client-side denial-of-service with no confidentiality or integrity impact (CVSS 4.0 VC:N/VI:N/VA:H), and should be triaged as a moderate, availability-only issue rather than a top priority. The vendor CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:P) indicates a network-reachable, low-complexity, unauthenticated trigger, but UI:P means the victim must actively connect their FreeRDP client to an attacker-controlled or compromised RDP server - so this is a reverse/malicious-server attack, not a server-side remotely-attackable flaw. No EPSS score, KEV listing, or public exploit was provided in the input, so exploitation status is 'no public exploit identified at time of analysis'; there is no signal of active exploitation or widespread automated abuse. A key limiting factor not captured by the raw 7.1 score is that the crash only affects clients using Linux serial-port redirection, a non-default and relatively uncommon configuration, which substantially narrows the real-world attack surface below what AV:N/PR:N alone would suggest. |
| Exploit ScenarioDerived | An attacker stands up a malicious RDP server (or compromises a legitimate one) and lures a victim running FreeRDP with Linux serial redirection enabled to connect to it. The server sends a serial IRP_MJ_READ or IRP_MJ_WRITE outside the normal create/close lifecycle, causing CommReadFile or CommWriteFile to dereference a null device handle and crash the client. No public exploit code was identified in the provided intelligence. |
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Alert meAnalysisAIv1 – Oct 14, 2026
Null pointer dereference in FreeRDP versions 2.0.0 through 3.31.x allows a malicious RDP server to crash Linux clients that have serial-port redirection enabled. The attacker sends IRP_MJ_READ or IRP_MJ_WRITE requests either before the serial channel is created or after it is closed, causing CommReadFile or CommWriteFile to dereference a null handle and terminate the client. This is an availability-only issue (CVSS 4.0 score 7.1, no confidentiality or integrity impact) that requires the victim to initiate a connection to the attacker-controlled server and have serial redirection active; no public exploit code has been identified at time of analysis.
RemediationAI
Vendor-released patch: 3.32.0. Upgrade FreeRDP to version 3.32.0 or later as soon as possible; this is the definitive fix per the GitHub security advisory GHSA-pw4j-ff39-9vjm. If immediate upgrade is not feasible, disable serial-port redirection in the FreeRDP client (e.g., remove the /serial or equivalent option) to prevent the vulnerable CommReadFile and CommWriteFile code paths from being invoked; this workaround eliminates serial device access but blocks the attack vector. Additionally, avoid connecting to untrusted or unfamiliar RDP servers, as the attack requires the victim to initiate a connection to a malicious server. No other specific compensating controls are identified; general network filtering of RDP traffic is not directly applicable because the issue is client-side.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
FreeRDP is an open-source implementation of the Remote Desktop Protocol (RDP). When serial-port device redirection is enabled, the client uses a virtual channel to handle serial I/O requests (IRPs) such as IRP_MJ_READ and IRP_MJ_WRITE. The vulnerability is a NULL pointer dereference (CWE-476) in the CommReadFile and CommWriteFile functions, which are reached only when serial redirection is configured on Linux. A malicious RDP server can send read or write IRPs outside the expected lifecycle-before the channel's create or after its close-so that the internal handle is NULL. The client then dereferences this null handle, leading to a crash. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N) indicates a network-based, low-complexity attack requiring no privileges and only passive user interaction (the user must initiate the connection), with sole impact being high availability loss. No exploit code or active exploitation is currently identified.
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- Exploit and PoC references, threat intelligence from 22 sources
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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
Malicious server crashes the connecting client, so AV:N/PR:N but UI:R (victim must connect); availability-only impact (A:H, C:N/I:N) with no scope change.
Primary rating from Vendor (vulncheck).
CVSS VectorVendor: vulncheck
Lifecycle Timeline
2DescriptionCVE.org
FreeRDP from 2.0.0 before 3.32.0 contains a null pointer dereference vulnerability that allows malicious RDP servers to crash clients by sending out-of-lifecycle serial IRPs. Attackers can send IRP_MJ_READ or IRP_MJ_WRITE before create or after close, causing CommReadFile or CommWriteFile to dereference a null handle and terminate clients using Linux serial redirection.
Articles & Coverage 1
Technical POC Analysis
CWE-476 (NULL pointer dereference), also tagged CWE-672 (operation after release), in FreeRDP's serial channel client: channels/serial/client/serialmain.c.
Full technical POC analysis - root cause, step-by-step exploitation and patch breakdown - is part of the Pro and Business plans.
Executive ViewAI
FreeRDP versions 2.0.0 through 3.31.x on Linux systems contain a null pointer dereference that can crash the RDP client when serial-port redirection is enabled. No public exploit identified at time of analysis, but the vulnerability requires a user to connect to a malicious RDP server, which could disrupt remote work for employees relying on serial devices. No vendor-released patch identified at time of analysis; leadership should prioritize interim mitigations to prevent productivity loss.
Disable serial-port redirection in FreeRDP client configurations where not essential; restrict outbound RDP traffic to trusted servers only; consider using alternative RDP clients unaffected by this vulnerability; monitor for unexpected client crashes and investigate signs of malicious RDP servers.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A null pointer dereference occurs when a program attempts to access memory through a pointer that has been set to NULL (address 0x0).
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
Use-after-free in FreeRDP xf_clipboard_format_equal before 3.23.0. Clipboard format comparison uses freed memory. Fifth
Use-after-free in FreeRDP xf_AppUpdateWindowFromSurface before 3.23.0. Surface-to-window update triggers memory corrupti
Use-after-free in FreeRDP xf_SetWindowMinMaxInfo before version 3.23.0. X11 client window management triggers memory cor
Use-after-free in FreeRDP xf_cliprdr_provide_data clipboard handling before 3.23.0. Clipboard data exchange triggers mem
FreeRDP IRP thread handler has a use-after-free where the IRP is freed by Complete() then accessed on the error path. Fi
FreeRDP drive read heap overflow when server-controlled read length exceeds IRP output buffer. Fixed in 3.20.1. PoC avai
FreeRDP client before 3.20.1 has a heap buffer overflow in AUDIN format processing. A malicious RDP server can corrupt m
Use-after-free in FreeRDP xf_AppUpdateWindowFromSurface before 3.23.0. Different code path from CVE-2026-25953. PoC and
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
EUVD-2026-101717
GHSA-mff9-5vqw-qr9q
NVD
CVE.org
EPSS
Vulnrichment
Exploit-DB