Is CVE-2008-3843 in the CISA KEV catalog?

No. CVE-2008-3843 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2008-3843?

CVE-2008-3843 has a CVSS v2 base score of 4.3 (MEDIUM).

What is the EPSS score for CVE-2008-3843?

CVE-2008-3843 has an EPSS score of 21.99% (97th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2008-3843

MEDIUMEPSS 97th pctl

4.3

CVSS v2

NVD

Description

Request Validation (aka the ValidateRequest filters) in ASP.NET in Microsoft .NET Framework with the MS07-040 update does not properly detect dangerous client input, which allows remote attackers to conduct cross-site scripting (XSS) attacks, as demonstrated by a query string containing a "<~/" (less-than tilde slash) sequence followed by a crafted STYLE element.

CWE-79Cross-Site Scripting (XSS)

CVSS v2 Vector

No CVSS vector data available.

Exploit Intelligence

21.99%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 2026-04-23.