Is CVE-2001-1533 being actively exploited?

CVE-2001-1533 is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

What is the CVSS score for CVE-2001-1533?

CVE-2001-1533 has a CVSS 3.1 base score of 5.3 (MEDIUM).

CVE-2001-1533

MEDIUM · CVSS 5.3EPSS 18.0%EU EUVD

Microsoft Internet Security and Acceleration (ISA) Server 2000 allows remote attackers to cause a denial of service via a flood of fragmented UDP packets. NOTE: the vendor disputes this issue, saying that it requires high bandwidth to exploit, and the server does not experience any instability. Therefore this "laws of physics" issue might not be included in CVE

Key facts

CVSS score: 5.3 (v3.1)
Severity: MEDIUM
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
EPSS score: 18.0% (97th percentile)
In CISA KEV: No
In EU EUVD: Yes (EUVD-2001-1510)
Published: December 31, 2001
NVD last modified: June 16, 2026
Status: Modified

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2001-1510 in the EU Vulnerability Database. Last updated in EUVD on January 16, 2025.

View on the EU Vulnerability Database

Affected products

microsoft / isa server

Certified products that may be affected

1 FIPS 140 or Common Criteria certified product, from automated matching by sec-certs.org.

ISA Server 2000 with Service Pack 1 and Feature Pack 1, Firewall - Microsoft Corporation - Common Criteria BSI-DSZ-CC-0218-2003 - archived

References

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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