How severe is CVE-1999-0867?

CVE-1999-0867 has a CVSS 2.0 base score of 5.0, rated medium severity.

Is CVE-1999-0867 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 22% (97th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-1999-0867?

CVE-1999-0867 primarily affects Microsoft Commercial Internet System. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-1999-0867?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-1999-0867 published?

CVE-1999-0867 was published on 1999-08-11 and last updated on 2026-06-16.

CVE-1999-0867

CVE-1999-0867 is a medium-severity vulnerability in Microsoft Commercial Internet System with a CVSS 2.0 base score of 5.0. Its EPSS exploit-prediction score of 22% places it in the 97th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-20.

Key facts

Severity: Medium (CVSS 2.0 base score 5.0)
EPSS exploit prediction: 22% (97th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Microsoft Commercial Internet System
Published: 1999-08-11
Last modified: 2026-06-16

Description

Denial of service in IIS 4.0 via a flood of HTTP requests with malformed headers.

Frequently asked questions

What is CVE-1999-0867?: Denial of service in IIS 4.0 via a flood of HTTP requests with malformed headers.
How severe is CVE-1999-0867?: CVE-1999-0867 has a CVSS 2.0 base score of 5.0, rated medium severity.
Is CVE-1999-0867 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 22% (97th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-1999-0867?: CVE-1999-0867 primarily affects Microsoft Commercial Internet System. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-1999-0867?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-1999-0867 published?: CVE-1999-0867 was published on 1999-08-11 and last updated on 2026-06-16.

References

Affected products (4)

cpe:2.3:a:microsoft:commercial_internet_system:2.0:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:commercial_internet_system:2.5:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:internet_information_server:4.0:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:site_server:3.0:unknown:commerce:*:*:*:*:*

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