CVE-2018-0798 [Exploited] | Microsoft OFFICE Out-of-bounds Write

CVE-2018-0798 is rated Critical Active Threat (95.2/100): CVSS High severity, with high exploitation likelihood (EPSS 94.06%, 100th percentile). CISA KEV confirms active exploitation (added 2021-11-03) affecting Microsoft / Office. a weakness (CWE-787) Unauthenticated remote administrative access may be possible. The CISA remediation deadline has passed—treat as an emergency patch priority.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-03-08	94.03%	94.06%	+0.02%
2	2026-02-27	94.09%	94.03%	-0.05%
3	2025-11-21	—	94.09%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-03-08

94.03%

94.06%

+0.02%

2026-02-27

94.09%

94.03%

-0.05%

2025-11-21

—

94.09%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
8.8	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/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: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.	2.8	5.9	[email protected]
8.8	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/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: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.	2.8	5.9	134c704f-9b21-4f2e-91b3-4a467353bcc0
9.3	2.0	HIGH	`AV:N/AC:M/Au:N/C:C/I:C/A:C` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:M) Exploitation needs some favorable conditions, but not exceptional ones. Authentication (AU:N) No authentication is required. Confidentiality impact (C:C) Complete confidentiality impact. Integrity impact (I:C) Complete integrity impact. Availability impact (A:C) Complete availability impact.	8.6	10.0	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

8.8

3.1

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/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: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.

2.8

5.9

[email protected]

8.8

3.1

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/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: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.

2.8

5.9

134c704f-9b21-4f2e-91b3-4a467353bcc0

9.3

2.0

HIGH

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

Access vector (AV:N): Can be exploited remotely over network reachability.
Access complexity (AC:M): Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:C): Complete confidentiality impact.
Integrity impact (I:C): Complete integrity impact.
Availability impact (A:C): Complete availability impact.

8.6

10.0

[email protected]

Affected software / configurations for CVE-2018-0798

Vendor	Product	Version	Raw CPE
microsoft	office	2007	cpe:2.3:a:microsoft:office:2007:sp3::::::
microsoft	office	2010	cpe:2.3:a:microsoft:office:2010:sp2::::::
microsoft	office	2013	cpe:2.3:a:microsoft:office:2013:sp1::::::
microsoft	office	2016	cpe:2.3:a:microsoft:office:2016:::::::*
microsoft	office	2016	cpe:2.3:a:microsoft:office:2016::::click-to-run:::
microsoft	office_compatibility_pack	—	cpe:2.3:a:microsoft:office_compatibility_pack:-:sp3::::::
microsoft	word	2007	cpe:2.3:a:microsoft:word:2007:sp3::::::
microsoft	word	2010	cpe:2.3:a:microsoft:word:2010:sp2::::::
microsoft	word	2013	cpe:2.3:a:microsoft:word:2013:sp1::::::
microsoft	word	2013	cpe:2.3:a:microsoft:word:2013:sp1:::rt:::*
microsoft	word	2016	cpe:2.3:a:microsoft:word:2016:::::::*

References for CVE-2018-0798

URL	Tags
http://www.securityfocus.com/bid/102370	Broken Link Third Party Advisory VDB Entry
http://www.securitytracker.com/id/1040153	Broken Link Third Party Advisory VDB Entry
https://0patch.blogspot.com/2018/01/bringing-abandoned-equation-editor-back.html	Third Party Advisory
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-0798	Patch Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-0798	US Government Resource

URL

CVE-2018-0798

CISA KEV Record for CVE-2018-0798

Exploit prediction scoring system (EPSS) score for CVE-2018-0798

Common vulnerability scoring system (CVSS) metrics for CVE-2018-0798

Weakness enumeration for CVE-2018-0798

Affected software / configurations for CVE-2018-0798

References for CVE-2018-0798