How severe is CVE-1999-1199?

CVE-1999-1199 has a CVSS 2.0 base score of 10.0, rated critical severity.

Is CVE-1999-1199 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 7% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-1999-1199?

CVE-1999-1199 affects Apache Http Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-1999-1199?

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-1999-1199 published?

CVE-1999-1199 was published on 1998-08-07 and last updated on 2026-06-16.

CVE-1999-1199

CVE-1999-1199 is a critical-severity vulnerability in Apache Http Server with a CVSS 2.0 base score of 10.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Critical (CVSS 2.0 base score 10.0)
EPSS exploit prediction: 7% (93rd percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Apache Http Server
Published: 1998-08-07
Last modified: 2026-06-16

Description

Apache WWW server 1.3.1 and earlier allows remote attackers to cause a denial of service (resource exhaustion) via a large number of MIME headers with the same name, aka the "sioux" vulnerability.

Frequently asked questions

What is CVE-1999-1199?: Apache WWW server 1.3.1 and earlier allows remote attackers to cause a denial of service (resource exhaustion) via a large number of MIME headers with the same name, aka the "sioux" vulnerability.
How severe is CVE-1999-1199?: CVE-1999-1199 has a CVSS 2.0 base score of 10.0, rated critical severity.
Is CVE-1999-1199 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 7% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-1999-1199?: CVE-1999-1199 affects Apache Http Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-1999-1199?: 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-1999-1199 published?: CVE-1999-1199 was published on 1998-08-07 and last updated on 2026-06-16.

References

Affected products (1)

cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*

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