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.
Affected products
freerdp: freerdp
References5
- github.com/FreeRDP/FreeRDP/security/advisories/GHSA-qmvw-52ph-q… ExploitVendor Advisory
- github.com/FreeRDP/FreeRDP/security/advisories/GHSA-5wr6-8m8j-3… Vendor Advisory
- github.com/FreeRDP/FreeRDP/commit/46848765f2a1134f8652f8760eefb… Patch
- github.com/FreeRDP/FreeRDP/commit/5370fb26fbf034ecd11d3026b6ad6… Patch
- www.vulncheck.com/advisories/freerdp-heap-buffer-overflow-via-r… Third Party Advisory
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 4.0
-
8.7
HIGH
Score source: CNA
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 1% percentile: 54 · as of 13 November 2026
- CWE
- CWE-191
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