Alibaba Cloud Linux 3 : 0116: freerdp (ALINUX3-SA-2026:0116)

medium Nessus Plugin ID 316584

Synopsis

The remote Alibaba Cloud Linux host is missing one or more security updates.

Description

The remote Alibaba Cloud Linux 3 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALINUX3-SA-2026:0116 advisory.

Package updates are available for Alibaba Cloud Linux 3 that fix the following vulnerabilities:

CVE-2026-25952:
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, `xf_SetWindowMinMaxInfo` dereferences a freed `xfAppWindow` pointer because `xf_rail_get_window` in `xf_rail_server_min_max_info` returns an unprotected pointer from the `railWindows` hash table, and the main thread can concurrently delete the window (via a window delete order) while the RAIL channel thread is still using the pointer. Version 3.23.0 fixes the issue.

CVE-2026-26986:
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, `rail_window_free` dereferences a freed `xfAppWindow` pointer during `HashTable_Free` cleanup because `xf_rail_window_common` calls `free(appWindow)` on title allocation failure without first removing the entry from the `railWindows` hash table, leaving a dangling pointer that is freed again on disconnect.
Version 3.23.0 fixes the vulnerability.

CVE-2026-27951:
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, the function `Stream_EnsureCapacity` can create an endless blocking loop. This may affect all client and server implementations using `FreeRDP`. For practical exploitation this will only work on 32bit systems where the available physical memory is `>= SIZE_MAX`. Version 3.23.0 contains a patch. No known workarounds are available.

CVE-2026-29775:
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0, a client-side heap out- of-bounds read/write occurs in FreeRDP's bitmap cache subsystem due to an off-by-one boundary check in bitmap_cache_put. A malicious server can send a CACHE_BITMAP_ORDER (Rev1) with cacheId equal to maxCells, bypassing the guard and accessing cells[] one element past the allocated array. This vulnerability is fixed in 3.24.0.

CVE-2026-31883:
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0, a size_t underflow in the IMA-ADPCM and MS-ADPCM audio decoders leads to heap-buffer-overflow write via the RDPSND audio channel. In libfreerdp/codec/dsp.c, the IMA-ADPCM and MS-ADPCM decoders subtract block header sizes from a size_t variable without checking for underflow. When nBlockAlign (received from the server) is set such that size % block_size == 0 triggers the header parsing at a point where size is smaller than the header (4 or 8 bytes), the subtraction wraps size to ~SIZE_MAX. The while (size > 0) loop then continues for an astronomical number of iterations. This vulnerability is fixed in 3.24.0.

CVE-2026-31884:
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0, division by zero in MS- ADPCM and IMA-ADPCM decoders when nBlockAlign is 0, leading to a crash. In libfreerdp/codec/dsp.c, both ADPCM decoders use size % block_size where block_size = context->common.format.nBlockAlign. The nBlockAlign value comes from the Server Audio Formats PDU on the RDPSND channel. The value 0 is not validated anywhere before reaching the decoder. When nBlockAlign = 0, the modulo operation causes a SIGFPE (floating point exception) crash. This vulnerability is fixed in 3.24.0.

CVE-2026-31885:
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0, there is an out-of- bounds read in MS-ADPCM and IMA-ADPCM decoders due to unchecked predictor and step_index values from input data. This vulnerability is fixed in 3.24.0.

CVE-2026-33985:
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.24.2, pixel data from adjacent heap memory is rendered to screen, potentially leaking sensitive data to the attacker. This issue has been patched in version 3.24.2.

Tenable has extracted the preceding description block directly from the Alibaba Cloud 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.

Plugin Details

Severity: Medium

ID: 316584

File Name: alinux3_sa_2026-0116.nasl

Version: 1.1

Type: Local

Family: Alibaba Cloud Linux Local Security Checks

Published: 5/25/2026

Updated: 5/25/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2026-31883

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.8

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

CVSS v4

Risk Factor: Medium

Base Score: 6.9

Threat Score: 5.5

Threat Vector: CVSS:4.0/E:P

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS Score Source: CVE-2026-26986

Vulnerability Information

CPE: cpe:/o:alibabacloud:alibaba_cloud_linux_3, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:freerdp-devel, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:libwinpr-devel, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:libwinpr, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:freerdp-doc, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:freerdp-libs, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:freerdp

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/Alibaba/release, Host/Alibaba/rpm-list

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 5/19/2026

Vulnerability Publication Date: 2/25/2026

Reference Information

CVE: CVE-2026-25952, CVE-2026-26986, CVE-2026-27951, CVE-2026-29775, CVE-2026-31883, CVE-2026-31884, CVE-2026-31885, CVE-2026-33985

Detections

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