CVE-2021-42277 [Medium] | Privilege Escalation in Visual Studio

CVE-2021-42277 is rated Low Risk (39.3/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.26%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2025-11-10	0.36%	0.26%	-0.09%
2	2025-09-01	0.28%	0.36%	+0.07%
3	2025-03-30	—	0.28%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2025-11-10

0.36%

0.26%

-0.09%

2025-09-01

0.28%

0.36%

+0.07%

2025-03-30

—

0.28%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.5	3.1	MEDIUM	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. 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:L) A normal user session is enough; they don’t have to be admin. 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.	1.8	3.6	[email protected]
7.8	3.1	HIGH	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. 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:L) A normal user session is enough; they don’t have to be admin. 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:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	1.8	5.9	[email protected]
4.6	2.0	MEDIUM	`AV:L/AC:L/Au:N/C:P/I:P/A:P` Click to expand Access vector (AV:L) Requires local access to the target system. Access complexity (AC:L) Exploitation conditions are straightforward and predictable. Authentication (AU:N) No authentication is required. Confidentiality impact (C:P) Partial confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:P) Partial availability impact.	3.9	6.4	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

5.5

3.1

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
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:L): A normal user session is enough; they don’t have to be admin.
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.

1.8

3.6

[email protected]

7.8

3.1

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
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:L): A normal user session is enough; they don’t have to be admin.
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:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

1.8

5.9

[email protected]

4.6

2.0

MEDIUM

AV:L/AC:L/Au:N/C:P/I:P/A:P Click to expand

Access vector (AV:L): Requires local access to the target system.
Access complexity (AC:L): Exploitation conditions are straightforward and predictable.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:P): Partial confidentiality impact.
Integrity impact (I:P): Partial integrity impact.
Availability impact (A:P): Partial availability impact.

3.9

6.4

[email protected]

Affected software / configurations for CVE-2021-42277

Vendor	Product	Version	Raw CPE
microsoft	visual_studio	2015	cpe:2.3:a:microsoft:visual_studio:2015:update3::::::
microsoft	visual_studio_2017	>= 15.0, <= 15.9	cpe:2.3:a:microsoft:visual_studio_2017::::::::
microsoft	visual_studio_2019	>= 16.0, <= 16.11	cpe:2.3:a:microsoft:visual_studio_2019::::::::
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	21h1	cpe:2.3:o:microsoft:windows_10:21h1:::::::*
microsoft	windows_10	1607	cpe:2.3:o:microsoft:windows_10:1607:::::::*
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_11	—	cpe:2.3:o:microsoft:windows_11:-::::::arm64:
microsoft	windows_11	—	cpe:2.3:o:microsoft:windows_11:-::::::x64:
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	2004	cpe:2.3:o:microsoft:windows_server_2016:2004:::::::*
microsoft	windows_server_2019	—	cpe:2.3:o:microsoft:windows_server_2019:-:::::::*
microsoft	windows_server_2022	—	cpe:2.3:o:microsoft:windows_server_2022:-:::::::*

References for CVE-2021-42277

URL	Tags
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42277	Patch Vendor Advisory
https://www.zerodayinitiative.com/advisories/ZDI-21-1306/	Third Party Advisory

URL

CVE-2021-42277 | Diagnostics Hub Standard Collector Elevation of Privilege Vulnerability

Exploit prediction scoring system (EPSS) score for CVE-2021-42277

Common vulnerability scoring system (CVSS) metrics for CVE-2021-42277

Weakness enumeration for CVE-2021-42277

Affected software / configurations for CVE-2021-42277

References for CVE-2021-42277