How severe is CVE-2021-41159?

CVE-2021-41159 has a CVSS 3.x base score of 5.8, rated medium severity. It is exploitable over network with high attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2021-41159 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-41159?

CVE-2021-41159 primarily affects Freerdp. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-41159?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-41159 published?

CVE-2021-41159 was published on 2021-10-21 and last updated on 2026-06-17.

CVE-2021-41159

CVE-2021-41159 is a medium-severity vulnerability in Freerdp with a CVSS 3.x base score of 5.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.

Key facts

Severity: Medium (CVSS 3.x base score 5.8)
CVSS v2: 6.8
EPSS exploit prediction: 1% (68th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Freerdp
Published: 2021-10-21
Last modified: 2026-06-17

Description

FreeRDP is a free implementation of the Remote Desktop Protocol (RDP), released under the Apache license. All FreeRDP clients prior to version 2.4.1 using gateway connections (`/gt:rpc`) fail to validate input data. A malicious gateway might allow client memory to be written out of bounds. This issue has been resolved in version 2.4.1. If you are unable to update then use `/gt:http` rather than /gt:rdp connections if possible or use a direct connection without a gateway.

Frequently asked questions

What is CVE-2021-41159?: FreeRDP is a free implementation of the Remote Desktop Protocol (RDP), released under the Apache license. All FreeRDP clients prior to version 2.4.1 using gateway connections (`/gt:rpc`) fail to validate input data. A malicious gateway might allow client memory to be written out of bounds. This issue has been resolved in version 2.4.1. If you are unable to update then use `/gt:http` rather than /gt:rdp connections if possible or use a direct connection without a gateway.
How severe is CVE-2021-41159?: CVE-2021-41159 has a CVSS 3.x base score of 5.8, rated medium severity. It is exploitable over network with high attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2021-41159 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-41159?: CVE-2021-41159 primarily affects Freerdp. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-41159?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-41159 published?: CVE-2021-41159 was published on 2021-10-21 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*

More vulnerabilities in Freerdp

CVE-2026-45700 — Critical (CVSS 9.8): FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.26.0, FreeRDP's planar bitmap decoder has…
CVE-2026-31806 — Critical (CVSS 9.8): FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0, the gdi_surface_bits() function…
CVE-2026-25997 — Critical (CVSS 9.8): FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, `xf_clipboard_format_equal`…
CVE-2026-25959 — Critical (CVSS 9.8): FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, `xf_cliprdr_provide_data_`…
CVE-2026-25955 — Critical (CVSS 9.8): FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0,…
CVE-2026-25953 — Critical (CVSS 9.8): FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0,…

All CVEs affecting Freerdp →

Other CWE-787 (Out-of-bounds Write) vulnerabilities

CVE-2026-42369 — Critical (CVSS 10.0): GV-VMS V20 is a Video Monitoring Software used to gather the feeds of many surveillance cameras and manage other…
CVE-2026-4746 — Critical (CVSS 10.0): Out-of-bounds Write vulnerability in timeplus-io proton (base/poco/Foundation/src‎ modules). This vulnerability is…
CVE-2025-43300 — Critical (CVSS 10.0): An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 15.8.5 and iPadOS…
CVE-2025-24201 — Critical (CVSS 10.0): An out-of-bounds write issue was addressed with improved checks to prevent unauthorized actions. This issue is fixed in…
CVE-2024-42479 — Critical (CVSS 10.0): llama.cpp provides LLM inference in C/C++. The unsafe `data` pointer member in the `rpc_tensor` structure can cause…
CVE-2024-39791 — Critical (CVSS 10.0): Stack-based buffer overflow vulnerabilities affecting Vonets industrial wifi bridge relays and wifi bridge…

Browse all CWE-787 (Out-of-bounds Write) vulnerabilities →