CVE-2021-34535

CVE-2021-34535 is a high-severity vulnerability in Microsoft Remote Desktop Client with a CVSS 3.x base score of 8.8. Its EPSS exploit-prediction score of 18% places it in the 97th percentile, indicating an elevated likelihood of exploitation.

Key facts

• Severity: High (CVSS 3.x base score 8.8)
• CVSS v2: 6.8
• EPSS exploit prediction: 18% (97th percentile)
• Actively exploited: Not listed in CISA KEV
• Affected product: Microsoft Remote Desktop Client
• Published: 2021-08-12
• Last modified: 2026-06-17

Description

Remote Desktop Client Remote Code Execution Vulnerability

Frequently asked questions

What is CVE-2021-34535?

Remote Desktop Client Remote Code Execution Vulnerability

How severe is CVE-2021-34535?

CVE-2021-34535 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-34535 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 18% (97th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-34535?

CVE-2021-34535 primarily affects Microsoft Remote Desktop Client. In total, 16 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-34535?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-34535 published?

CVE-2021-34535 was published on 2021-08-12 and last updated on 2026-06-17.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34535

Affected products (16)

• cpe:2.3:a:microsoft:remote_desktop_client:-:*:*:*:*:windows:*:*
• cpe:2.3:o:microsoft:windows_10:-:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_10:20h2:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_10:21h1:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_10:1607:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_10:1809:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_10:1909:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_10:2004:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_7:-:sp1:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_8.1:-:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_rt_8.1:-:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_server_2016:-:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_server_2019:-:*:*:*:*:*:*:*

More vulnerabilities in Microsoft Remote Desktop Client

• CVE-2026-42985 — High (CVSS 8.8): Heap-based buffer overflow in Remote Desktop Client allows an unauthorized attacker to execute code over a network.
• CVE-2026-32157 — High (CVSS 8.8): Use after free in Remote Desktop Client allows an unauthorized attacker to execute code over a network.
• CVE-2025-58718 — High (CVSS 8.8): Use after free in Remote Desktop Client allows an unauthorized attacker to execute code over a network.
• CVE-2025-48817 — High (CVSS 8.8): Relative path traversal in Remote Desktop Client allows an unauthorized attacker to execute code over a network.
• CVE-2025-26645 — High (CVSS 8.8): Relative path traversal in Remote Desktop Client allows an unauthorized attacker to execute code over a network.
• CVE-2024-38131 — High (CVSS 8.8): Clipboard Virtual Channel Extension Remote Code Execution Vulnerability

All CVEs affecting Microsoft Remote Desktop Client →