Is CVE-2008-5553 in the CISA KEV catalog?

No. CVE-2008-5553 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2008-5553?

CVE-2008-5553 has a CVSS v2 base score of 4.3 (MEDIUM).

What is the EPSS score for CVE-2008-5553?

CVE-2008-5553 has an EPSS score of 11.56% (95th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2008-5553

MEDIUMEPSS 95th pctl

4.3

CVSS v2

NVD

Description

The XSS Filter in Microsoft Internet Explorer 8.0 Beta 2 disables itself upon encountering a certain X-XSS-Protection HTTP header, which allows remote attackers to bypass the XSS protection mechanism and conduct XSS attacks by injecting this header after a CRLF sequence. NOTE: the vendor has reportedly stated that the XSS Filter intentionally does not attempt to "address every conceivable XSS attack scenario."

CWE-79Cross-Site Scripting (XSS)

CVSS v2 Vector

No CVSS vector data available.

Exploit Intelligence

11.56%probability of exploitation in 30 days

95thpercentile

Very high risk: more likely to be exploited than 95% 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.