CVE-2018-8373

Exp

A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer, aka "Scripting Engine Memory Corruption Vulnerability." This affects Internet Explorer 9, Internet Explorer 11, Internet Explorer 10. This CVE ID is unique from CVE-2018-8353, CVE-2018-8355, CVE-2018-8359, CVE-2018-8371, CVE-2018-8372, CVE-2018-8385, CVE-2018-8389, CVE-2018-8390.

Published: 2018-08-15 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-8373 is rated Critical Active Threat (84.7/100): CVSS High severity, with high exploitation likelihood (EPSS 61.91%, 99th percentile). CISA KEV confirms active exploitation (added 2022-03-25) affecting Microsoft / Internet Explorer Scripting Engine. a weakness (CWE-787) Unauthenticated remote administrative access may be possible. The CISA remediation deadline has passed—treat as an emergency patch priority.

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

CISA KEV Record for CVE-2018-8373

Name: Microsoft Scripting Engine Memory Corruption Vulnerability · CISA KEV detail

Exploit added: 2022-03-25

Action due: 2022-04-15

Required action: Apply updates per vendor instructions.

Exploit prediction scoring system (EPSS) score for CVE-2018-8373

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 2026-06-15 82.49% 61.91% -20.58%
2 2026-03-17 82.42% 82.49% +0.07%
3 2025-11-21 — 82.42% —

Full EPSS history (55 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-8373

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:H/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:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
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.
 1.6 5.9 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:H/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:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
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.
 1.6 5.9 134c704f-9b21-4f2e-91b3-4a467353bcc0
7.6 2.0 HIGH
AV:N/AC:H/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:H)
Exploitation requires uncommon or highly specific conditions.
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.
 4.9 10.0 [email protected]

Weakness enumeration for CVE-2018-8373

Affected software / configurations for CVE-2018-8373

Vendor Product Version Raw CPE
microsoft internet_explorer 11 cpe:2.3:a:microsoft:internet_explorer:11:*:*:*:*:*:*:*
microsoft internet_explorer 10 cpe:2.3:a:microsoft:internet_explorer:10:*:*:*:*:*:*:*
microsoft internet_explorer 9 cpe:2.3:a:microsoft:internet_explorer:9:*:*:*:*:*:*:*

References for CVE-2018-8373

cvelogic Threat Intelligence