No exploitation reported

CVE-2001-1533

No exploitation reported by the sources we read.

Published2001-12-31

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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

Timeline

dates in UTC

2001-12-3105:00CVE publishedNVD
2026-10-2319:23EPSS crossed 10 %FIRST EPSS

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2001-1533?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2001-1533?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Microsoft isa server

Branch	Affected	Fixed in	Source
2000.x	= 2000	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionnone2024-03-21
OpenCVESSVC decisionnone—
CISA-ADPCVSS 3.15.32025-01-16
NVDCVSS 2.05read 2026-10-23
FIRST EPSSEPSS score18.0 %read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Published: 2001-12-31
Last Modified: 2026-06-16
NVD status: Modified

Frequently asked questions

What is CVE-2001-1533?

Is CVE-2001-1533 actively exploited?

Active exploitation of CVE-2001-1533 has not been confirmed. Its EPSS score was 18.0% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

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

CVE-2001-1533 has a CVSS v3 base score of 5.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

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