CVE-2023-40576Network attack vector

Client crash via unchecked RLE source reads

Published Aug 31, 2023 · Updated Feb 13, 2025

Out-of-bounds read in FreeRDP 3.0.0-beta1 through 3.0.0-beta2 allows remote attackers to crash RDP clients via crafted bitmap data. RleDecompress reads pbSrcBuffer while decoding RLE bitmap data without first verifying that enough source bytes remain for each operation. Exploitation requires a FreeRDP-based client to process the malformed bitmap stream; the documented consequence is an error or client crash, not data modification.

CVSS severity7.5
High
EPSS probability1.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in FreeRDP 3.0.0-beta1 through 3.0.0-beta2 allows remote attackers to crash RDP clients via crafted bitmap data. RleDecompress reads pbSrcBuffer while decoding RLE bitmap data without first verifying that enough source bytes remain for each operation. Exploitation requires a FreeRDP-based client to process the malformed bitmap stream; the documented consequence is an error or client crash, not data modification.

The record

CVE
CVE-2023-40576
Published
Aug 31, 2023
Updated
Feb 13, 2025
Vendor
FreeRDP
Product
FreeRDP
Classifications
CWE-125, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 31, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record 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=>= 3.0.0-beta1, < 3.0.0-beta3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FreeRDP · FreeRDPversion=>= 3.0.0-beta1, < 3.0.0-beta3

Published CVSS scores

7.5NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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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