Is CVE-2004-0203 in the CISA KEV catalog?

No. CVE-2004-0203 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2004-0203?

CVE-2004-0203 has a CVSS v2 base score of 4.3 (MEDIUM).

What is the EPSS score for CVE-2004-0203?

CVE-2004-0203 has an EPSS score of 20.98% (97th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2004-0203

MEDIUMEPSS 97th pctl

4.3

CVSS v2

NVD

Description

Cross-site scripting (XSS) vulnerability in Outlook Web Access for Exchange Server 5.5 Service Pack 4 allows remote attackers to insert arbitrary script and spoof content in HTML email or web caches via an HTML redirect query.

CWE-79Cross-Site Scripting (XSS)

CVSS v2 Vector

No CVSS vector data available.

Exploit Intelligence

20.98%probability of exploitation in 30 days

97thpercentile

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

References

http://www.kb.cert.org/vuls/id/948750
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2004/ms04-026
https://exchange.xforce.ibmcloud.com/vulnerabilities/16583
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A2016

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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.