CVE-2011-0091

CVE-2011-0091 is a medium-severity vulnerability in Microsoft Windows 7 with a CVSS 2.0 base score of 6.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

Description

Kerberos in Microsoft Windows Server 2008 R2 and Windows 7 does not prevent a session from changing from strong encryption to DES encryption, which allows man-in-the-middle attackers to spoof network traffic and obtain sensitive information via a DES downgrade, aka "Kerberos Spoofing Vulnerability."

Frequently asked questions

What is CVE-2011-0091?
Kerberos in Microsoft Windows Server 2008 R2 and Windows 7 does not prevent a session from changing from strong encryption to DES encryption, which allows man-in-the-middle attackers to spoof network traffic and obtain sensitive information via a DES downgrade, aka "Kerberos Spoofing Vulnerability."
How severe is CVE-2011-0091?
CVE-2011-0091 has a CVSS 2.0 base score of 6.4, rated medium severity.
Is CVE-2011-0091 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-0091?
CVE-2011-0091 primarily affects Microsoft Windows 7. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2011-0091?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2011-0091 published?
CVE-2011-0091 was published on 2011-02-10 and last updated on 2026-06-16.

References

Affected products (3)

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