Heap-based buffer overflow in FreeRDP - #VU134508
Published: June 15, 2026
Vulnerability identifier: #VU134508
CSH Severity: High
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
CVE-ID: N/A
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: FreeRDP
Affected software:
FreeRDP
FreeRDP
Detailed vulnerability description
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to a heap-based buffer overflow caused by integer overflow in avc444_ensure_buffer in libfreerdp/codec/h264.c when decoding AVC444 GFX frames from a malicious RDP server. A remote attacker can send crafted surface dimensions and H.264 bitstream content to execute arbitrary code.
Exploitation requires a FreeRDP client build using libfreerdp AVC444 decompression with RDPGFX AVC444 negotiated and an H.264 decoder backend enabled.
Remediation
Install security update from vendor's website.