CVE-2020-16899 | Windows TCP/IP Denial of Service Vulnerability

<p>A denial of service vulnerability exists when the Windows TCP/IP stack improperly handles ICMPv6 Router Advertisement packets. An attacker who successfully exploited this vulnerability could cause a target system to stop responding.</p> <p>To exploit this vulnerability, an attacker would have to send specially crafted ICMPv6 Router Advertisement packets to a remote Windows computer. The vulnerability would not allow an attacker to execute code or to elevate user rights directly.</p> <p>The update addresses the vulnerability by correcting how the Windows TCP/IP stack handles ICMPv6 Router Advertisement packets.</p>

Published: 2020-10-16 Last update: 2026-02-23 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-16899 is rated Moderate Risk (62.7/100): CVSS High severity, with high exploitation likelihood (EPSS 40.98%, 97th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-16899

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-18 42.31% 40.98% -1.33%
2 2025-11-21 45.01% 42.31% -2.70%
3 2025-11-18 — 45.01% —

Full EPSS history (21 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-16899

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
7.8 2.0 HIGH
AV:N/AC:L/Au:N/C:N/I:N/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:C)
Complete availability impact.
 10.0 6.9 [email protected]

Weakness enumeration for CVE-2020-16899

Affected software / configurations for CVE-2020-16899

Vendor Product Version Raw CPE
microsoft windows_10 1709 cpe:2.3:o:microsoft:windows_10:1709:*:*:*:*:*:*:*
microsoft windows_10 1803 cpe:2.3:o:microsoft:windows_10:1803:*:*:*:*:*:*:*
microsoft windows_10 1809 cpe:2.3:o:microsoft:windows_10:1809:*:*:*:*:*:*:*
microsoft windows_10 1903 cpe:2.3:o:microsoft:windows_10:1903:*:*:*:*:*:*:*
microsoft windows_10 1909 cpe:2.3:o:microsoft:windows_10:1909:*:*:*:*:*:*:*
microsoft windows_10 2004 cpe:2.3:o:microsoft:windows_10:2004:*:*:*:*:*:*:*
microsoft windows_server_2016 1903 cpe:2.3:o:microsoft:windows_server_2016:1903:*:*:*:*:*:*:*
microsoft windows_server_2016 1909 cpe:2.3:o:microsoft:windows_server_2016:1909:*:*:*:*:*:*:*
microsoft windows_server_2016 2004 cpe:2.3:o:microsoft:windows_server_2016:2004:*:*:*:*:*:*:*
microsoft windows_server_2019 — cpe:2.3:o:microsoft:windows_server_2019:-:*:*:*:*:*:*:*

References for CVE-2020-16899

cvelogic Threat Intelligence