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CVE-2026-55564 Details

Description

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, the glyph_cache_get function in libfreerdp/cache/glyph.c checks whether index is greater than cache->number instead of greater than or equal to it. A malicious RDP server can use GLYPH_FRAGMENT_USE replay in update_process_glyph_fragments to make the default cache receive index 254 when cache->number is 254, reading one pointer beyond the entries array and dereferencing it as a glyph. This can crash the client and may disclose adjacent heap data. This issue is fixed in version 3.27.0.

Metrics

CVSS 3.x Severity and Vector Strings:

NIST: [email protected]CVSS-B:7.1 HIGHVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H

CNA: [email protected]CVSS-B:5.4 MEDIUMVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L

References to Advisories, Solutions, and Tools

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URL	Source(s)	Tag(s)
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-6xmj-pr98-cx4c	CISA-ADP	ExploitMitigationVendor Advisory
https://github.com/FreeRDP/FreeRDP/commit/c29324750e3cbcba8761f147b7a5235cc686930f	[email protected]	Patch
https://github.com/FreeRDP/FreeRDP/pull/12885	[email protected]	Issue TrackingPatch
https://github.com/FreeRDP/FreeRDP/releases/tag/3.27.0	[email protected]	Release Notes
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-6xmj-pr98-cx4c	[email protected]	ExploitMitigationVendor Advisory

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-125	Out-of-bounds Read	[email protected]
CWE-193	Off-by-one Error	[email protected]

Affected Products

Product	Versions
freerdp freerdp	< 3.27.0
CPE cpe:2.3:a:freerdp:freerdp:::::::: Remediation No remediation found in references.

Change History

3 change records found show changes

Date	Action	Recorded By
Sep 22, 2026	Initial Analysis	[email protected]
Aug 25, 2026	CVE Modified	CISA-ADP
Aug 19, 2026	New CVE Received	[email protected]