CVE-2001-1533

Name: CVE-2001-1533
Creator: NVD / NIST
Published: 2001-12-31T05:00:00+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.3/10EPSS 18.01%

Last modified Jun 16, 2026

CVE-2001-1533 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. 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. EPSS estimates a 18.01% chance of exploitation in the next 30 days.

Description

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

Metrics

CVSS 3.1

5.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS Probability

18.01%

96.8th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Microsoft	Isa Server	2000

References

Timeline

Published: Dec 31, 2001
Last Modified: Jun 16, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2001-1533?

How severe is CVE-2001-1533?

CVE-2001-1533 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 18.01% probability of exploitation in the next 30 days.

How do I fix CVE-2001-1533?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2001-1533?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST