How severe is CVE-2001-0904?

CVE-2001-0904 has a CVSS 2.0 base score of 5.0, rated medium severity.

Is CVE-2001-0904 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 7% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2001-0904?

CVE-2001-0904 primarily affects Microsoft Internet Explorer. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2001-0904?

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

When was CVE-2001-0904 published?

CVE-2001-0904 was published on 2001-11-20 and last updated on 2026-06-16.

CVE-2001-0904

CVE-2001-0904 is a medium-severity vulnerability in Microsoft Internet Explorer with a CVSS 2.0 base score of 5.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 2.0 base score 5.0)
EPSS exploit prediction: 7% (93rd percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Microsoft Internet Explorer
Published: 2001-11-20
Last modified: 2026-06-16

Description

Internet Explorer 5.5 and 6 with the Q312461 (MS01-055) patch modifies the HTTP_USER_AGENT (UserAgent) information that indicates that the patch has been installed, which could allow remote malicious web sites to more easily identify and exploit vulnerable clients.

Frequently asked questions

What is CVE-2001-0904?: Internet Explorer 5.5 and 6 with the Q312461 (MS01-055) patch modifies the HTTP_USER_AGENT (UserAgent) information that indicates that the patch has been installed, which could allow remote malicious web sites to more easily identify and exploit vulnerable clients.
How severe is CVE-2001-0904?: CVE-2001-0904 has a CVSS 2.0 base score of 5.0, rated medium severity.
Is CVE-2001-0904 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 7% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2001-0904?: CVE-2001-0904 primarily affects Microsoft Internet Explorer. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2001-0904?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2001-0904 published?: CVE-2001-0904 was published on 2001-11-20 and last updated on 2026-06-16.

References

Affected products (2)

cpe:2.3:a:microsoft:internet_explorer:5.5:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:internet_explorer:6.0:*:*:*:*:*:*:*

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