Is CVE-2008-5553 being actively exploited?

CVE-2008-5553 is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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

CVE-2008-5553 has a CVSS 2.0 base score of 4.3 (MEDIUM).

CVE-2008-5553

MEDIUM · CVSS 4.3EPSS 11.6%EU EUVD

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."

Key facts

CVSS score: 4.3 (v2.0)
Severity: MEDIUM
CVSS vector: AV:N/AC:M/Au:N/C:N/I:P/A:N
Weakness (CWE): CWE-79
EPSS score: 11.6% (96th percentile)
In CISA KEV: No
In EU EUVD: Yes (EUVD-2008-5528)
Published: December 12, 2008
NVD last modified: June 16, 2026
Status: Modified

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2008-5528 in the EU Vulnerability Database. Last updated in EUVD on August 7, 2024.

View on the EU Vulnerability Database

Affected products

microsoft / internet explorer

References

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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