CVE-2026-44420Public exploitNetwork attack vector

Server crash via undersized cliprdr allocation

Published May 29, 2026 · Updated May 29, 2026

Heap-based buffer overflow in FreeRDP before 3.26.0 allows remote authenticated users to crash an RDP server via a crafted clipboard PDU. The cliprdr capability parser reallocates a heap buffer to the client-controlled capabilitySetLength, then writes a 12-byte general capability structure without ensuring that allocation is large enough. An authenticated RDP client with clipboard redirection can reach the flaw; the resulting heap corruption also creates a code-execution risk, but the advisory demonstrates only a crash.

CVSS severity8.8
High
EPSS probability3.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in FreeRDP before 3.26.0 allows remote authenticated users to crash an RDP server via a crafted clipboard PDU. The cliprdr capability parser reallocates a heap buffer to the client-controlled capabilitySetLength, then writes a 12-byte general capability structure without ensuring that allocation is large enough. An authenticated RDP client with clipboard redirection can reach the flaw; the resulting heap corruption also creates a code-execution risk, but the advisory demonstrates only a crash.

The record

CVE
CVE-2026-44420
Published
May 29, 2026
Updated
May 29, 2026
Vendor
FreeRDP
Product
FreeRDP
Classifications
CWE-131, CWE-122, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 29, 2026CVE publishedPublication date reported by the CVE source.
  2. May 29, 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=< 3.26.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

FreeRDP · FreeRDPversion=< 3.26.0

Published CVSS scores

8.8GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-131Incorrect Calculation of Buffer Size
CWE-122Heap-based Buffer Overflow
T1499.004Application or System Exploitation

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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