CVE-2009-0580

CVE-2009-0580 is a medium-severity vulnerability in Apache Tomcat with a CVSS 2.0 base score of 4.3. Its EPSS exploit-prediction score of 94% places it in the 100th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-200.

Key facts

Description

Apache Tomcat 4.1.0 through 4.1.39, 5.5.0 through 5.5.27, and 6.0.0 through 6.0.18, when FORM authentication is used, allows remote attackers to enumerate valid usernames via requests to /j_security_check with malformed URL encoding of passwords, related to improper error checking in the (1) MemoryRealm, (2) DataSourceRealm, and (3) JDBCRealm authentication realms, as demonstrated by a % (percent) value for the j_password parameter.

Frequently asked questions

What is CVE-2009-0580?
Apache Tomcat 4.1.0 through 4.1.39, 5.5.0 through 5.5.27, and 6.0.0 through 6.0.18, when FORM authentication is used, allows remote attackers to enumerate valid usernames via requests to /j_security_check with malformed URL encoding of passwords, related to improper error checking in the (1) MemoryRealm, (2) DataSourceRealm, and (3) JDBCRealm authentication realms, as demonstrated by a % (percent) value for the j_password parameter.
How severe is CVE-2009-0580?
CVE-2009-0580 has a CVSS 2.0 base score of 4.3, rated medium severity.
Is CVE-2009-0580 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 94% (100th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2009-0580?
CVE-2009-0580 primarily affects Apache Tomcat. In total, 87 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2009-0580?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2009-0580 published?
CVE-2009-0580 was published on 2009-06-05 and last updated on 2026-06-16.

References

Affected products (87)

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