FreeRDP versions 3.28.0 and earlier contain a heap buffer overflow in the server-side RAIL channel handler (rail_server_handle_messages() in channels/rail/server/rail_main.c). When processing a RAIL PDU header, the code subtracts RAIL_PDU_HEADER_LENGTH from the peer-controlled orderLength field without first verifying orderLength is at least the header length. For orderLength values 0..3 this causes an unsigned integer underflow to a very large size, which bypasses the Stream_EnsureRemainingCapacity() capacity check (due to pointer arithmetic wraparound) and is then passed to WTSVirtualChannelRead(), resulting in an out-of-bounds heap write. A malicious or compromised RDP client can exploit this to corrupt the heap and crash the server. Fixed in FreeRDP 3.29.0.
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Affected Vendors & Products
References
History
Sat, 01 Aug 2026 12:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | FreeRDP versions 3.28.0 and earlier contain a heap buffer overflow in the server-side RAIL channel handler (rail_server_handle_messages() in channels/rail/server/rail_main.c). When processing a RAIL PDU header, the code subtracts RAIL_PDU_HEADER_LENGTH from the peer-controlled orderLength field without first verifying orderLength is at least the header length. For orderLength values 0..3 this causes an unsigned integer underflow to a very large size, which bypasses the Stream_EnsureRemainingCapacity() capacity check (due to pointer arithmetic wraparound) and is then passed to WTSVirtualChannelRead(), resulting in an out-of-bounds heap write. A malicious or compromised RDP client can exploit this to corrupt the heap and crash the server. Fixed in FreeRDP 3.29.0. | |
| Title | FreeRDP 3.28.0 Heap Buffer Overflow via RAIL orderLength Underflow | |
| First Time appeared |
Freerdp
Freerdp freerdp |
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| Weaknesses | CWE-191 | |
| CPEs | cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Freerdp
Freerdp freerdp |
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| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: VulnCheck
Published:
Updated: 2026-08-01T12:22:18.323Z
Reserved: 2026-07-29T13:04:41.947Z
Link: CVE-2026-67298
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OpenCVE Enrichment
Updated: 2026-08-01T13:45:02Z