CVE-2025-21354 [High] | RCE in 365 Apps

CVE-2025-21354 is rated Moderate Risk (62.7/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.73%). Review affected assets and schedule remediation.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-04-22	1.46%	1.73%	+0.27%
2	2026-02-23	1.11%	1.46%	+0.34%
3	2026-02-22	—	1.11%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-04-22

1.46%

1.73%

+0.27%

2026-02-23

1.11%

1.46%

+0.34%

2026-02-22

—

1.11%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
8.4	3.1	HIGH	`CVSS:3.1/AV:L/AC:L/PR:N/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: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: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.	2.5	5.9	[email protected]
7.8	3.1	HIGH	`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/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:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. 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]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

8.4

3.1

HIGH

CVSS:3.1/AV:L/AC:L/PR:N/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: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: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.

2.5

5.9

[email protected]

7.8

3.1

HIGH

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/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:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
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]

Affected software / configurations for CVE-2025-21354

Vendor	Product	Version	Raw CPE
microsoft	365_apps	—	cpe:2.3:a:microsoft:365_apps:-::::enterprise::x64:*
microsoft	365_apps	—	cpe:2.3:a:microsoft:365_apps:-::::enterprise::x86:*
microsoft	office	2019	cpe:2.3:a:microsoft:office:2019:::::-:x64:*
microsoft	office	2019	cpe:2.3:a:microsoft:office:2019:::::-:x86:*
microsoft	office_long_term_servicing_channel	2021	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021::::::x64:
microsoft	office_long_term_servicing_channel	2021	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021::::::x86:
microsoft	office_long_term_servicing_channel	2021	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:::::macos::
microsoft	office_long_term_servicing_channel	2024	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024::::::x64:
microsoft	office_long_term_servicing_channel	2024	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024::::::x86:
microsoft	office_long_term_servicing_channel	2024	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:::::macos::
microsoft	office_online_server	< 16.0.10416.20047	cpe:2.3:a:microsoft:office_online_server::::::::

References for CVE-2025-21354

URL	Tags
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21354	Patch Vendor Advisory

URL

CVE-2025-21354 | Microsoft Excel Remote Code Execution Vulnerability

Exploit prediction scoring system (EPSS) score for CVE-2025-21354

Common vulnerability scoring system (CVSS) metrics for CVE-2025-21354

Weakness enumeration for CVE-2025-21354

Affected software / configurations for CVE-2025-21354

References for CVE-2025-21354