How severe is CVE-1999-1223?

CVE-1999-1223 has a CVSS 2.0 base score of 5.0, rated medium severity.

Is CVE-1999-1223 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 23% (97th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-1999-1223?

CVE-1999-1223 affects Microsoft Internet Information Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-1999-1223?

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

When was CVE-1999-1223 published?

CVE-1999-1223 was published on 1999-12-31 and last updated on 2026-06-16.

CVE-1999-1223

CVE-1999-1223 is a medium-severity vulnerability in Microsoft Internet Information Server with a CVSS 2.0 base score of 5.0. Its EPSS exploit-prediction score of 23% places it in the 97th percentile, indicating an elevated likelihood of exploitation.

Key facts

Severity: Medium (CVSS 2.0 base score 5.0)
EPSS exploit prediction: 23% (97th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Microsoft Internet Information Server
Published: 1999-12-31
Last modified: 2026-06-16

Description

IIS 3.0 allows remote attackers to cause a denial of service via a request to an ASP page in which the URL contains a large number of / (forward slash) characters.

Frequently asked questions

What is CVE-1999-1223?: IIS 3.0 allows remote attackers to cause a denial of service via a request to an ASP page in which the URL contains a large number of / (forward slash) characters.
How severe is CVE-1999-1223?: CVE-1999-1223 has a CVSS 2.0 base score of 5.0, rated medium severity.
Is CVE-1999-1223 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 23% (97th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-1999-1223?: CVE-1999-1223 affects Microsoft Internet Information Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-1999-1223?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-1999-1223 published?: CVE-1999-1223 was published on 1999-12-31 and last updated on 2026-06-16.

References

Affected products (1)

cpe:2.3:a:microsoft:internet_information_server:3.0:*:*:*:*:*:*:*

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