Detections
Analytics
TencentOS Server 4: freerdp (TSSA-2026:0966)
high Nessus Plugin ID 343514
Synopsis
The remote TencentOS Server 4 host is missing one or more security updates.Description
The version of Tencent Linux installed on the remote TencentOS Server 4 host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the TSSA-2026:0966 advisory.Package updates are available for TencentOS Server 4 that fix the following vulnerabilities:
CVE-2026-55194:
A flaw was found in FreeRDP. A remote attacker, specifically a malicious TS Gateway, can exploit a heap- buffer-overflow vulnerability by sending a specially crafted Remote Desktop Protocol (RDP) response. This occurs because the client incorrectly uses a smaller `alloc_hint` value instead of the actual `StubLength` for buffer capacity during response reassembly. This allows attacker-controlled data to be written beyond the intended buffer, leading to a client crash and potentially enabling arbitrary code execution.
CVE-2026-55193:
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, FreeRDP clients using TS Gateway accept a server-controlled max_xmit_frag value in libfreerdp/core/gateway/rpc_bind.c without bounding it to the 4088-byte ReceiveFragment allocation. A malicious gateway can advertise 65535 and then send a response fragment of the same length, causing rpc_channel_read in libfreerdp/core/gateway/rpc.c to write up to 65535 bytes into the smaller ReceiveFragment buffer. This can crash the client and may permit code execution through attacker-controlled heap corruption. This issue is fixed in version 3.27.0.
CVE-2026-55191:
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, FreeRDP clients that negotiate RDPGFX AVC444 with an H.264 decoder backend calculate the intermediate YUV444 allocation size in libfreerdp/codec/h264.c with 32-bit multiplication in avc444_ensure_buffer. A malicious RDP server can supply surface dimensions for which piDstStride multiplied by padDstHeight wraps to a small nonzero value, causing winpr_aligned_recalloc to allocate an undersized buffer before YUV420CombineToYUV444 writes using the actual stride and rectangle dimensions. This can cause a client crash and may permit code execution through attacker-influenced heap corruption. This issue is fixed in version 3.27.0.
Tenable has extracted the preceding description block directly from the Tencent Linux security advisory.
Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.
Solution
Update the affected packages.See Also
Plugin Details
Severity: High
ID: 343514
File Name: tencentos_TSSA_2026_0966.nasl
Version: 1.1
Type: Local
Family: Tencent Local Security Checks
Published: 9/7/2026
Updated: 9/7/2026
Supported Sensors: Nessus
Risk Information
VPR
Risk Factor: Medium
Score: 4.9
Percentile: 58.23
CVSS v2
Risk Factor: Critical
Base Score: 10
Temporal Score: 7.4
Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C
CVSS Score Source: CVE-2026-55194
CVSS v3
Risk Factor: High
Base Score: 8.8
Temporal Score: 7.7
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C
CVSS v4
Risk Factor: High
Base Score: 8.7
Threat Score: 6.3
Threat Vector: CVSS:4.0/E:U
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Vulnerability Information
CPE: cpe:/o:tencent:tencentos_server:4, p-cpe:/a:tencent:tencentos_server:freerdp
Required KB Items: Host/local_checks_enabled, Host/cpu, Host/etc/os-release, Host/TencentOS/rpm-list
Exploit Ease: No known exploits are available
Patch Publication Date: 9/3/2026
Vulnerability Publication Date: 6/18/2026