CVE-2026-55192Public exploitNetwork attack vector

Client memory disclosure and crash via H.264 dimensions

Published Aug 19, 2026 · Updated Aug 25, 2026

Out-of-bounds read in FreeRDP before 3.27.0 allows remote attackers to disclose client memory or crash clients via H.264 RDPGFX frames. The H.264 backends replace validated surface dimensions with smaller bitstream-sized YUV planes, while YUV-to-RGB conversion still consumes surface-sized rectangles. Exploitation requires a client with H.264 support to connect to a malicious RDP server and negotiate AVC420 or AVC444; server-only and H.264-disabled builds are unaffected.

CVSS severity7.2
High
EPSS probability0.50%
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 before 3.27.0 allows remote attackers to disclose client memory or crash clients via H.264 RDPGFX frames. The H.264 backends replace validated surface dimensions with smaller bitstream-sized YUV planes, while YUV-to-RGB conversion still consumes surface-sized rectangles. Exploitation requires a client with H.264 support to connect to a malicious RDP server and negotiate AVC420 or AVC444; server-only and H.264-disabled builds are unaffected.

The record

CVE
CVE-2026-55192
Published
Aug 19, 2026
Updated
Aug 25, 2026
Vendor
FreeRDP
Product
FreeRDP
Classifications
CWE-125
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 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=< 3.27.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FreeRDP · FreeRDPversion=< 3.27.0

Published CVSS scores

7.2GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/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-125Out-of-bounds Read

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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