CVE-2026-55564: Freerdp

High severity, CVSS 7.1. EPSS: 0.4% chance of exploitation in the next 30 days.

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.

Affected products

• Freerdp Freerdp: before 3.27.0 (fixed in 3.27.0)

Published 2026-08-19. Last modified 2026-09-22.