# CVE-2026-55564

## Summary

- **CVE ID:** CVE-2026-55564
- **Severity:** MEDIUM
- **CVSS Score:** 5.4 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L)
- **CWE:** CWE-125, CWE-193
- **Published:** Aug 19, 2026
- **Last Modified:** Aug 25, 2026

## 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.

## Affected Products

- FreeRDP — FreeRDP (< 3.27.0)

## References

- [CNA](https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-6xmj-pr98-cx4c)
- [CNA](https://github.com/FreeRDP/FreeRDP/pull/12885)
- [CNA](https://github.com/FreeRDP/FreeRDP/commit/c29324750e3cbcba8761f147b7a5235cc686930f)
- [CNA](https://github.com/FreeRDP/FreeRDP/releases/tag/3.27.0)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.27%
- **EPSS Percentile:** 18.4

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._