CVE-2022-39282 in FreeRDP
Summary
by MITRE • 10/13/2022
FreeRDP is a free remote desktop protocol library and clients. FreeRDP based clients on unix systems using `/parallel` command line switch might read uninitialized data and send it to the server the client is currently connected to. FreeRDP based server implementations are not affected. Please upgrade to 2.8.1 where this issue is patched. If unable to upgrade, do not use parallel port redirection (`/parallel` command line switch) as a workaround.
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Analysis
by VulDB Data Team • 11/29/2025
CVE-2022-39282 represents a critical information disclosure vulnerability within the FreeRDP library ecosystem that affects Unix-based client implementations. This vulnerability specifically manifests when clients utilize the parallel port redirection functionality through the `/parallel` command line switch, creating a scenario where uninitialized memory segments are inadvertently transmitted to connected remote servers. The flaw stems from improper memory initialization within the parallel port handling code path, where data structures allocated for parallel port communication contain residual values from previous operations rather than being properly cleared before use. This represents a classic example of uninitialized memory access that can lead to information leakage, making it classified under CWE-457 as "Use of Uninitialized Variable" and potentially related to CWE-248 as "Uncaught Exception" in certain execution contexts. The vulnerability operates at the application layer and specifically targets the client-side implementation of FreeRDP, leaving server-side components unaffected as noted in the advisory.
The operational impact of this vulnerability extends beyond simple information disclosure, as the uninitialized data potentially transmitted could contain sensitive information from other applications or system processes that previously occupied the same memory locations. Attackers leveraging this vulnerability could potentially reconstruct fragments of memory contents, including credentials, session tokens, or other confidential data that may have resided in the uninitialized memory segments. This makes the vulnerability particularly concerning in environments where FreeRDP clients connect to untrusted servers or where the parallel port redirection feature is actively used. The attack vector requires a specific client configuration involving the parallel port redirection switch, which aligns with ATT&CK technique T1071.004 for application layer protocol usage, though the actual exploitation would involve memory manipulation rather than traditional network protocol exploitation. The vulnerability's impact is mitigated by the fact that it only affects client implementations and not server components, but the potential for data leakage remains significant.
Organizations utilizing FreeRDP clients on Unix systems should prioritize immediate upgrade to version 2.8.1 where the vulnerability has been patched through proper memory initialization procedures. The patch addresses the root cause by ensuring that all memory allocated for parallel port handling is properly initialized before use, preventing the leakage of residual data. For environments where immediate upgrading is not feasible, the recommended workaround involves avoiding the use of the `/parallel` command line switch entirely, effectively disabling the problematic functionality. This mitigation strategy aligns with defensive programming practices and follows the principle of least privilege by eliminating unnecessary features that could expose the system to information disclosure risks. Security administrators should also consider implementing network monitoring to detect unusual data patterns that might indicate exploitation attempts, as the vulnerability's impact would manifest as anomalous data transmission from client systems to remote servers. The vulnerability serves as a reminder of the importance of proper memory management in network protocol implementations and highlights the necessity of thorough testing for uninitialized memory access issues in security-critical software components.