Severity by source
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/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
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Primary rating from Vendor (GitHub_M).
CVSS VectorVendor: GitHub_M
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/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
Lifecycle Timeline
3DescriptionCVE.org
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.26.0, FreeRDP's planar bitmap decoder has an out-of-bounds heap write when decoding RLE planar data. In libfreerdp/codec/planar.c, freerdp_bitmap_decompress_planar() validates the X destination coordinate nXDst against the caller-provided destination stride (nDstStep) even when it is writing into the internal temp buffer pTempData. An attacker can bypass the check with a large nDstStep and a large nXDst, causing planar_decompress_plane_rle() to write past the end of pTempData. This vulnerability is fixed in 3.26.0.
AnalysisAI
Out-of-bounds heap write in FreeRDP versions prior to 3.26.0 allows remote attackers to corrupt memory in the planar bitmap decoder when an RDP client connects to a malicious or compromised server. The flaw lives in freerdp_bitmap_decompress_planar() in libfreerdp/codec/planar.c, where attacker-controlled stride and X-destination values bypass bounds checks against the internal pTempData buffer. No public exploit identified at time of analysis, but the issue is fixed upstream in 3.26.0.
Technical ContextAI
FreeRDP is the widely used open-source implementation of Microsoft's Remote Desktop Protocol, embedded in many Linux/Unix RDP clients, thin clients, and virtualization tooling (per CPE cpe:2.3:a:freerdp:freerdp). The vulnerability is a classic CWE-787 out-of-bounds write in the RDP planar bitmap codec used to decompress RLE-encoded bitmap updates from a server. The validation logic in freerdp_bitmap_decompress_planar() checks the destination X coordinate (nXDst) against the caller-supplied destination stride (nDstStep), but this stride applies to the eventual output surface - not the smaller internal scratch buffer pTempData. When the decoder routes data through pTempData via planar_decompress_plane_rle(), an attacker who supplies a sufficiently large nDstStep paired with a large nXDst passes the check yet writes past the end of the temp heap allocation.
RemediationAI
Vendor-released patch: upgrade libfreerdp and any bundled clients to FreeRDP 3.26.0 or later, as called out in the upstream advisory at https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-mpxh-8fq3-x8mh. Operators of Linux distributions should track their distro security trackers for backported fixes to the 3.x packages and rebuild dependent applications (Remmina, GNOME Connections, etc.) against the patched library. As a compensating control until patched binaries are deployed, restrict outbound RDP (TCP/3389 and UDP/3389) from workstations to only known internal jump hosts via host or perimeter firewall - this blocks the attacker-server vector at the cost of breaking ad-hoc RDP to external endpoints. Where users must connect to untrusted servers, advise against doing so from the vulnerable client and prefer a hardened or Microsoft mstsc client temporarily; note this only mitigates, it does not eliminate, MITM-on-path scenarios against legitimate servers.
Use-after-free in FreeRDP xf_clipboard_format_equal before 3.23.0. Clipboard format comparison uses freed memory. Fifth
Use-after-free in FreeRDP xf_AppUpdateWindowFromSurface before 3.23.0. Surface-to-window update triggers memory corrupti
Use-after-free in FreeRDP xf_SetWindowMinMaxInfo before version 3.23.0. X11 client window management triggers memory cor
Use-after-free in FreeRDP xf_cliprdr_provide_data clipboard handling before 3.23.0. Clipboard data exchange triggers mem
FreeRDP IRP thread handler has a use-after-free where the IRP is freed by Complete() then accessed on the error path. Fi
FreeRDP drive read heap overflow when server-controlled read length exceeds IRP output buffer. Fixed in 3.20.1. PoC avai
FreeRDP client before 3.20.1 has a heap buffer overflow in AUDIN format processing. A malicious RDP server can corrupt m
Use-after-free in FreeRDP xf_AppUpdateWindowFromSurface before 3.23.0. Different code path from CVE-2026-25953. PoC and
FreeRDP is a free implementation of the Remote Desktop Protocol. Rated critical severity (CVSS 9.8), this vulnerability
FreeRDP is a free implementation of the Remote Desktop Protocol (RDP), released under the Apache license. Rated critical
FreeRDP is a free implementation of the Remote Desktop Protocol (RDP), released under the Apache license. Rated critical
FreeRDP is a free implementation of the Remote Desktop Protocol (RDP), released under the Apache license. Rated critical
Same weakness CWE-787 – Out-of-bounds Write
View allSame technique Memory Corruption
View allVendor StatusVendor
SUSE
Severity: Critical| Product | Status |
|---|---|
| openSUSE Tumbleweed | Fixed |
| SUSE Linux Enterprise Desktop 15 SP7 | Fixed |
| SUSE Linux Enterprise Desktop 15 SP7 | Fixed |
| SUSE Linux Enterprise Module for Package Hub 15 SP7 | Fixed |
| SUSE Linux Enterprise Module for Package Hub 15 SP7 | Fixed |
| SUSE Linux Enterprise Server 15 SP7 | Fixed |
| SUSE Linux Enterprise Server 15 SP7 | Fixed |
| SUSE Linux Enterprise Server 16.0 | Fixed |
| SUSE Linux Enterprise Server 16.1 | Fixed |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | Fixed |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | Fixed |
| SUSE Linux Enterprise Server for SAP applications 16.0 | Fixed |
| SUSE Linux Enterprise Server for SAP applications 16.1 | Fixed |
| SUSE Linux Enterprise Workstation Extension 15 SP7 | Fixed |
| SUSE Linux Enterprise Workstation Extension 15 SP7 | Fixed |
| openSUSE Leap 16.0 | Fixed |
| SUSE Linux Enterprise Server 12 SP5 | Fixed |
| SUSE Linux Enterprise Server 12 SP5-LTSS | Fixed |
| SUSE Linux Enterprise Server 12 SP5-LTSS Extended Security | Fixed |
| SUSE Linux Enterprise Server 15 SP4 | Fixed |
| SUSE Linux Enterprise Server 15 SP5 | Fixed |
| SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 | Fixed |
| SUSE Linux Enterprise Server for SAP Applications 12 SP5 | Fixed |
| SUSE Linux Enterprise Desktop 12 SP2 | Fixed |
| SUSE Linux Enterprise Desktop 12 SP3 | Fixed |
| SUSE Linux Enterprise Desktop 12 SP4 | Fixed |
| SUSE Linux Enterprise Desktop 15 SP4 | Fixed |
| SUSE Linux Enterprise Desktop 15 SP5 | Fixed |
| SUSE Linux Enterprise Module for Package Hub 15 SP4 | Fixed |
| SUSE Linux Enterprise Module for Package Hub 15 SP5 | Fixed |
| SUSE Linux Enterprise Module for Package Hub 15 SP6 | Fixed |
| SUSE Linux Enterprise Server 12 SP2 | Fixed |
| SUSE Linux Enterprise Server 12 SP3 | Fixed |
| SUSE Linux Enterprise Server 12 SP4 | Fixed |
| SUSE Linux Enterprise Server for SAP Applications 12 SP2 | Fixed |
| SUSE Linux Enterprise Server for SAP Applications 12 SP3 | Fixed |
| SUSE Linux Enterprise Server for SAP Applications 12 SP4 | Fixed |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | Fixed |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | Fixed |
| SUSE Linux Enterprise Software Development Kit 12 SP2 | Fixed |
| SUSE Linux Enterprise Software Development Kit 12 SP3 | Fixed |
| SUSE Linux Enterprise Software Development Kit 12 SP4 | Fixed |
| SUSE Linux Enterprise Software Development Kit 12 SP5 | Fixed |
| SUSE Linux Enterprise Workstation Extension 12 SP2 | Fixed |
| SUSE Linux Enterprise Workstation Extension 12 SP3 | Fixed |
| SUSE Linux Enterprise Workstation Extension 12 SP4 | Fixed |
| SUSE Linux Enterprise Workstation Extension 12 SP5 | Fixed |
| SUSE Linux Enterprise Workstation Extension 15 SP4 | Fixed |
| SUSE Linux Enterprise Workstation Extension 15 SP5 | Fixed |
| openSUSE Leap 15.4 | Fixed |
| openSUSE Leap 15.5 | Fixed |
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-33436