CVE-2021-24086 [High] | Denial of Service in Windows 10

CVE-2021-24086 is rated High Risk (69.6/100): CVSS High severity, with high exploitation likelihood (EPSS 58.96%, 99th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +8.15% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	50.81%	58.96%	+8.15%
2	2026-04-21	47.18%	50.81%	+3.63%
3	2026-01-17	—	47.18%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

50.81%

58.96%

+8.15%

2026-04-21

47.18%

50.81%

+3.63%

2026-01-17

—

47.18%

—

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]
5.0	2.0	MEDIUM	`AV:N/AC:L/Au:N/C:N/I:N/A:P` 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:P) Partial availability impact.	10.0	2.9	[email protected]

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]

5.0

2.0

MEDIUM

AV:N/AC:L/Au:N/C:N/I:N/A:P 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:P): Partial availability impact.

10.0

2.9

[email protected]

Affected software / configurations for CVE-2021-24086

Vendor	Product	Version	Raw CPE
microsoft	windows_10	—	cpe:2.3:o:microsoft:windows_10:-:::::::*
microsoft	windows_10	20h2	cpe:2.3:o:microsoft:windows_10:20h2:::::::*
microsoft	windows_10	1607	cpe:2.3:o:microsoft:windows_10:1607:::::::*
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	1909	cpe:2.3:o:microsoft:windows_10:1909:::::::*
microsoft	windows_10	2004	cpe:2.3:o:microsoft:windows_10:2004:::::::*
microsoft	windows_7	—	cpe:2.3:o:microsoft:windows_7:-:sp1::::::
microsoft	windows_8.1	—	cpe:2.3:o:microsoft:windows_8.1:-:::::::*
microsoft	windows_rt_8.1	—	cpe:2.3:o:microsoft:windows_rt_8.1:-:::::::*
microsoft	windows_server_2008	—	cpe:2.3:o:microsoft:windows_server_2008:-:sp2::::::
microsoft	windows_server_2008	r2	cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:::::x64:*
microsoft	windows_server_2012	—	cpe:2.3:o:microsoft:windows_server_2012:-:::::::*
microsoft	windows_server_2012	r2	cpe:2.3:o:microsoft:windows_server_2012:r2:::::::*
microsoft	windows_server_2016	—	cpe:2.3:o:microsoft:windows_server_2016:-:::::::*
microsoft	windows_server_2016	20h2	cpe:2.3:o:microsoft:windows_server_2016:20h2:::::::*
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-2021-24086

URL	Tags
http://packetstormsecurity.com/files/163499/Windows-TCP-IP-Denial-Of-Service.html	Third Party Advisory VDB Entry
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-24086	Patch Vendor Advisory

URL

CVE-2021-24086 | Windows TCP/IP Denial of Service Vulnerability

Exploit prediction scoring system (EPSS) score for CVE-2021-24086

Common vulnerability scoring system (CVSS) metrics for CVE-2021-24086

Weakness enumeration for CVE-2021-24086

Affected software / configurations for CVE-2021-24086

References for CVE-2021-24086