Freerdp Freerdp
CVE-2026-55564
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.
What this means for your business
- It affects Freerdp. It matters if your company, or a supplier that handles your data, runs it.
- Code showing how to exploit it has been published, but real attacks have not been confirmed.
- An attacker can use it remotely, over a network, without a login, but only after tricking someone into an action such as opening a file or a link.
- FIRST's prediction model gives it a 0.3% chance of attack attempts being seen in the next 30 days, ranking above 26% of all known flaws.
What to do
- 1Check whether your company or your suppliers run Freerdp, and which version. The affected versions are listed further down this page.
- 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.
Not sure if your company is exposed?
Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.
Scoring
- CVSS
- 5.4 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L- Weakness
- CWE-125
- Assigned by
- security-advisories@github.com
Dates
- Published
- 2026-08-19
- Last modified
- 2026-09-22
- Sources
- NVD
Affected products
- Freerdp Freerdp- 3.27.0
As listed in the NVD configuration data. Not a statement about your estate.