How severe is CVE-2019-1109?

CVE-2019-1109 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2019-1109 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-1109?

CVE-2019-1109 primarily affects Microsoft Office. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-1109?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2019-1109 published?

CVE-2019-1109 was published on 2019-07-15 and last updated on 2026-06-17.

CVE-2019-1109

CVE-2019-1109 is a critical-severity vulnerability in Microsoft Office with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v2: 6.4
EPSS exploit prediction: 4% (90th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Microsoft Office
Published: 2019-07-15
Last modified: 2026-06-17

Description

A spoofing vulnerability exists when Microsoft Office Javascript does not check the validity of the web page making a request to Office documents.An attacker who successfully exploited this vulnerability could read or write information in Office documents.The security update addresses the vulnerability by correcting the way that Microsoft Office Javascript verifies trusted web pages., aka 'Microsoft Office Spoofing Vulnerability'.

Frequently asked questions

What is CVE-2019-1109?: A spoofing vulnerability exists when Microsoft Office Javascript does not check the validity of the web page making a request to Office documents.An attacker who successfully exploited this vulnerability could read or write information in Office documents.The security update addresses the vulnerability by correcting the way that Microsoft Office Javascript verifies trusted web pages., aka 'Microsoft Office Spoofing Vulnerability'.
How severe is CVE-2019-1109?: CVE-2019-1109 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2019-1109 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-1109?: CVE-2019-1109 primarily affects Microsoft Office. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-1109?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2019-1109 published?: CVE-2019-1109 was published on 2019-07-15 and last updated on 2026-06-17.

References

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1109

Affected products (5)

cpe:2.3:a:microsoft:office:2013:sp1:*:*:*:*:*:*
cpe:2.3:a:microsoft:office:2013:sp1:*:*:rt:*:*:*
cpe:2.3:a:microsoft:office:2016:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:office:2019:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:office_365:-:*:*:*:proplus:*:*:*

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