Is CVE-2001-1533 in the CISA KEV catalog?

No. CVE-2001-1533 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2001-1533?

CVE-2001-1533 has a CVSS v3 base score of 5.3 (MEDIUM).

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

CVE-2001-1533 has an EPSS score of 18.01% (97th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2001-1533

MEDIUMEPSS 97th pctl

5.3

CVSS v3

NVD

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

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityLow

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

Exploit Intelligence

18.01%probability of exploitation in 30 days

97thpercentile

Very high risk: more likely to be exploited than 97% of all known CVEs.

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-16.