How severe is CVE-2019-1255?

CVE-2019-1255 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2019-1255 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-1255?

CVE-2019-1255 primarily affects Microsoft Windows Defender. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-1255?

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

When was CVE-2019-1255 published?

CVE-2019-1255 was published on 2019-09-23 and last updated on 2026-06-17.

CVE-2019-1255

CVE-2019-1255 is a high-severity vulnerability in Microsoft Windows Defender with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 4% (89th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Microsoft Windows Defender
Published: 2019-09-23
Last modified: 2026-06-17

Description

A denial of service vulnerability exists when Microsoft Defender improperly handles files, aka 'Microsoft Defender Denial of Service Vulnerability'.

Frequently asked questions

What is CVE-2019-1255?: A denial of service vulnerability exists when Microsoft Defender improperly handles files, aka 'Microsoft Defender Denial of Service Vulnerability'.
How severe is CVE-2019-1255?: CVE-2019-1255 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2019-1255 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-1255?: CVE-2019-1255 primarily affects Microsoft Windows Defender. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-1255?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2019-1255 published?: CVE-2019-1255 was published on 2019-09-23 and last updated on 2026-06-17.

References

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1255

Affected products (6)

cpe:2.3:a:microsoft:windows_defender:-:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:forefront_endpoint_protection_2010:-:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:security_essentials:-:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:system_center_endpoint_protection:*:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:system_center_endpoint_protection:2012:-:*:*:*:*:*:*
cpe:2.3:a:microsoft:system_center_endpoint_protection:2012:r2:*:*:*:*:*:*

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