FreeRDP: Out-of-bounds read in glyph_cache_get via crafted glyph fragments

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-55564
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-19 18:16:45 UTC
Updated2026-08-19 18:16:45 UTC
DescriptionFreeRDP 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.

Risk And Classification

Primary CVSS: v3.1 5.4 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L

EPSS: 0.003690000 probability, percentile 0.301520000 (date 2026-08-20)

Problem Types: CWE-125 | CWE-193 | CWE-125 CWE-125: Out-of-bounds Read | CWE-193 CWE-193: Off-by-one Error

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.4MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L
3.1CNADECLARED5.4MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA FreeRDP FreeRDP affected < 3.27.0 Not specified

References

ReferenceSourceLinkTags
github.com/FreeRDP/FreeRDP/pull/12885 [email protected] github.com
github.com/FreeRDP/FreeRDP/security/advisories/GHSA-6xmj-pr98-cx4c [email protected] github.com
github.com/FreeRDP/FreeRDP/releases/tag/3.27.0 [email protected] github.com
github.com/FreeRDP/FreeRDP/commit/c29324750e3cbcba8761f147b7a5235cc686930f [email protected] github.com
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