High severity · published Jul 10, 2026
CVE-2026-55827
FreeRDP: Heap out-of-bounds write in RemoteFX (RFX) Cache Bitmap V3 decode
8.8
CVSS
0.5%
EPSS
No
On KEV
Description
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.1, FreeRDP clients launched with the non-default /cache:codec:rfx option pass desktop stride and height to RemoteFX decoding for Cache Bitmap V3 data while allocating bitmap->data only for the smaller DstWidth and DstHeight in gdi_Bitmap_Decompress, allowing a malicious RDP server to trigger a heap out-of-bounds write with attacker-controlled offset and content. This issue is fixed in version 3.27.1.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 45% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FR
FreeRDP · FreeRDP
< 3.27.1 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-55827
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-55827
Patch
https://github.com/FreeRDP/FreeRDP/commit/e58adf922ea4c0d5495e59a1fe488d70092e0e3e
Patch
https://github.com/FreeRDP/FreeRDP/pull/12899
Release Notes
https://github.com/FreeRDP/FreeRDP/releases/tag/3.27.1
Exploit
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-c495-h83v-3prp
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