How severe is CVE-2008-5556?

CVE-2008-5556 has a CVSS 2.0 base score of 4.3, rated medium severity.

Is CVE-2008-5556 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 11% (95th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2008-5556?

CVE-2008-5556 affects Microsoft Internet Explorer. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2008-5556?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2008-5556 published?

CVE-2008-5556 was published on 2008-12-12 and last updated on 2026-06-16.

CVE-2008-5556

CVE-2008-5556 is a medium-severity vulnerability in Microsoft Internet Explorer with a CVSS 2.0 base score of 4.3. Its EPSS exploit-prediction score of 11% places it in the 95th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 2.0 base score 4.3)
EPSS exploit prediction: 11% (95th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Microsoft Internet Explorer
Published: 2008-12-12
Last modified: 2026-06-16

Description

The XSS Filter in Microsoft Internet Explorer 8.0 Beta 2 does not recognize attack patterns designed to operate against web pages that are encoded with utf-7, which allows remote attackers to bypass the XSS protection mechanism and conduct XSS attacks by injecting crafted utf-7 content. NOTE: the vendor reportedly disputes this issue, stating "Behaviour is by design.

Frequently asked questions

What is CVE-2008-5556?: The XSS Filter in Microsoft Internet Explorer 8.0 Beta 2 does not recognize attack patterns designed to operate against web pages that are encoded with utf-7, which allows remote attackers to bypass the XSS protection mechanism and conduct XSS attacks by injecting crafted utf-7 content. NOTE: the vendor reportedly disputes this issue, stating "Behaviour is by design.
How severe is CVE-2008-5556?: CVE-2008-5556 has a CVSS 2.0 base score of 4.3, rated medium severity.
Is CVE-2008-5556 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 11% (95th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2008-5556?: CVE-2008-5556 affects Microsoft Internet Explorer. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2008-5556?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2008-5556 published?: CVE-2008-5556 was published on 2008-12-12 and last updated on 2026-06-16.

References

Affected products (1)

cpe:2.3:a:microsoft:internet_explorer:8:beta2:*:*:*:*:*:*

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