VulnTideExploited vulnerabilities, by vendor. Data as of 28 Oct 2026.
Known exploitedIn CISA's KEV catalog since 3 November 2021Ransomware use: unknown
Microsoft Windows

CVE-2021-34448: Microsoft Windows Scripting Engine Memory Corruption Vulnerability

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 3 Nov 2021, 110 days after the CVE record was published.

How likely is exploitation in the next 30 days?
40.1%

EPSS score, percentile 98.6 of all scored records

How severe?
6.8 Medium

CVSS v3.1 base score, given by the CNA

What should I do?

Required action (CISA), due 17 Nov 2021: Apply updates per vendor instructions.

Advisories and patches (1)

Which versions are affected?

Affected: 10.0.10240.0 up to, not including, 10.0.10240.19003; 10.0.14393.0 up to, not including, 10.0.14393.4530; 10.0.17763.0 up to, not including, 10.0.17763.2061; 10.0.0 up to, not including, 10.0.17763.2061; 10.0.0 up to, not including, 10.0.18363.1679; 10.0.0 up to, not including, 10.0.19041.1110; 10.0.0 up to, not including, 10.0.19042.1110; 10.0.0 up to, not including, 10.0.19043.1110; 6.1.0 up to, not including, 6.1.7601.25661; 6.1.0 up to, not including, 6.1.7601.25661; 6.3.0 up to, not including, 6.3.9600.20069; 6.1.7601.0 up to, not including, 6.1.7601.25661; 6.2.9200.0 up to, not including, 6.2.9200.23409; 6.3.9600.0 up to, not including, 6.3.9600.20069; 10.0.14393.0 up to, not including, 10.0.14393.4530; 10.0.17763.0 up to, not including, 10.0.17763.2061

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

What to do

Required action, set by CISA

Apply updates per vendor instructions.

CISA due date for this action: 17 November 2021.

Advisories and patches

Linked from CISA's catalog entry

Affected products and versions

As listed in the CVE record.

Microsoft Windows 10 Version 1507
StatusVersions
Affected10.0.10240.0 up to, not including, 10.0.10240.19003
Microsoft Windows 10 Version 1607
StatusVersions
Affected10.0.14393.0 up to, not including, 10.0.14393.4530
Microsoft Windows 10 Version 1809
StatusVersions
Affected10.0.17763.0 up to, not including, 10.0.17763.2061
Microsoft Windows 10 Version 1809
StatusVersions
Affected10.0.0 up to, not including, 10.0.17763.2061
Microsoft Windows 10 Version 1909
StatusVersions
Affected10.0.0 up to, not including, 10.0.18363.1679
Microsoft Windows 10 Version 2004
StatusVersions
Affected10.0.0 up to, not including, 10.0.19041.1110
Microsoft Windows 10 Version 20H2
StatusVersions
Affected10.0.0 up to, not including, 10.0.19042.1110
Microsoft Windows 10 Version 21H1
StatusVersions
Affected10.0.0 up to, not including, 10.0.19043.1110
Microsoft Windows 7
StatusVersions
Affected6.1.0 up to, not including, 6.1.7601.25661
Microsoft Windows 7 Service Pack 1
StatusVersions
Affected6.1.0 up to, not including, 6.1.7601.25661
Microsoft Windows 8.1
StatusVersions
Affected6.3.0 up to, not including, 6.3.9600.20069
Microsoft Windows Server 2008 R2 Service Pack 1
StatusVersions
Affected6.1.7601.0 up to, not including, 6.1.7601.25661
Microsoft Windows Server 2012
StatusVersions
Affected6.2.9200.0 up to, not including, 6.2.9200.23409
Microsoft Windows Server 2012 R2
StatusVersions
Affected6.3.9600.0 up to, not including, 6.3.9600.20069
Microsoft Windows Server 2016
StatusVersions
Affected10.0.14393.0 up to, not including, 10.0.14393.4530
Microsoft Windows Server 2019
StatusVersions
Affected10.0.17763.0 up to, not including, 10.0.17763.2061

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

About this vulnerability

Microsoft Windows Scripting Engine contains an unspecified vulnerability that allows for memory corruption.

Summary: CISA's KEV catalog, as of 28 Oct 2026.

  • CISA added CVE-2021-34448 to its Known Exploited Vulnerabilities (KEV) catalog on 3 Nov 2021.
  • CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
  • The due date CISA sets for the required action is 17 Nov 2021.
  • The CVE record was published on 16 Jul 2021, 110 days before it was added to KEV.
  • The CVE record carries a CVSS v3.1 base score of 6.8 (Medium), given by its CNA.
  • FIRST's EPSS model puts the probability of exploitation in the next 30 days at 40.1% (percentile 98.6), as of 28 Oct 2026.
  • CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.

Description

Scripting Engine Memory Corruption Vulnerability

Scripting Engine Memory Corruption Vulnerability

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

Weakness

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.

Timeline

DateEvent
16 Jul 2021CVE record published
3 Nov 2021Added to CISA KEV
17 Nov 2021CISA due date for the required action
10 Aug 2026CVE record last updated

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