CVE-2026-69159
Description
A flaw was found in FreeRDP, an implementation of the Remote Desktop Protocol. A malicious RDP server can exploit an out-of-bounds read vulnerability by sending a malformed planar bitmap or surface update. This causes the client's decoder to read beyond its allocated buffer, which can lead to a client crash, resulting in a denial of service. Additionally, this flaw may disclose sensitive information from adjacent memory.
Statement
An out-of-bounds read vulnerability was found in FreeRDP's planar bitmap decoder (libfreerdp/codec/planar.c). Functions planar_decompress_plane_rle and planar_decompress_plane_rle_only fail to verify that the source buffer contains the required raw bytes specified by a control byte. A malicious RDP server can send a truncated planar bitmap or surface update claiming additional raw bytes, causing the client to read past the source buffer boundary. This can lead to a client application crash or partial disclosure of adjacent client memory.
Mitigation
To mitigate this vulnerability, disable RDP planar graphics codec acceleration in client settings or force alternative graphics rendering modes (such as standard RemoteFX or H.264) when connecting to untrusted RDP servers.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.4 | N/A | 5.4 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | Required | N/A | Required |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | Low | N/A | Low |
| Integrity Impact | None | N/A | None |
| Availability Impact | Low | N/A | Low |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
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