{"id":"CVE-2026-55564","title":"FreeRDP is a free implementation of the Remote Desktop Protocol","summary":"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 malic…","severity":"medium","cvss":5.4,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L","cwe":["CWE-125","CWE-193"],"vendor":"freerdp","product":"freerdp","affected":["freerdp < 3.27.0"],"patched":["freerdp 3.27.0"],"published":"2026-08-19","updated":"2026-09-22","sourceUpdated":"2026-09-22T19:44:08.997","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-55564","references":[{"url":"https://github.com/FreeRDP/FreeRDP/commit/c29324750e3cbcba8761f147b7a5235cc686930f","label":"security-advisories@github.com"},{"url":"https://github.com/FreeRDP/FreeRDP/pull/12885","label":"security-advisories@github.com"},{"url":"https://github.com/FreeRDP/FreeRDP/releases/tag/3.27.0","label":"security-advisories@github.com"},{"url":"https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-6xmj-pr98-cx4c","label":"security-advisories@github.com"},{"url":"https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-6xmj-pr98-cx4c","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-55564.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-55564"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2519813"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-55564"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55564"}],"tags":["nvd","csaf","vex","red-hat"],"epss":0.00334,"epssPercentile":0.26902,"ingestedAt":"2026-09-09T21:22:45.541Z","slug":"CVE-2026-55564","body":"## Overview\n\nFreeRDP 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.\n\n## Affected\n\n- `freerdp < 3.27.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `freerdp 3.27.0`\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-09-22 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-55564.json)","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":29.7,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}