Vulnerability 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.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/FreeRDP/FreeRDP/commit/c29324750e3cbcba8761f147b7a5235cc68693
- https://github.com/FreeRDP/FreeRDP/pull/12885
- https://github.com/FreeRDP/FreeRDP/releases/tag/3.27.0
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-6xmj-pr98-cx4c
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-6xmj-pr98-cx4c
FAQ
What is CVE-2026-55564?
CVE-2026-55564 is a vulnerability with a CVSS score of 5.4 (MEDIUM). 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...
How severe is CVE-2026-55564?
CVE-2026-55564 has been rated MEDIUM with a CVSS base score of 5.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-55564?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.