{
    "id": "CVE-2009-0580",
    "published": "2009-06-05 16:00:00",
    "last_modified": "2026-06-16 23:05:20",
    "cvss_score": "4.3",
    "cvss_severity": "MEDIUM",
    "cvss_version": "2.0",
    "cvss_vector": "AV:N/AC:M/Au:N/C:P/I:N/A:N",
    "cwe": "CWE-200",
    "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.",
    "epss_score": "0.94440",
    "epss_percentile": "0.99850",
    "kev": 0,
    "kev_due": null,
    "has_exploit": 1,
    "updated_at": "2026-09-26 18:16:37",
    "priority": {
        "rank": 2,
        "label": "Patch early",
        "why": "A public exploit exists."
    },
    "products": [
        {
            "vendor": "apache",
            "product": "tomcat"
        }
    ],
    "kev_detail": null,
    "exploits": [
        {
            "source": "exploit-db",
            "ref_id": "33023",
            "title": "Apache Tomcat 6.0.18 - Form Authentication Existing/Non-Existing 'Username' Enumeration",
            "date": "2009-06-03",
            "url": "https://www.exploit-db.com/exploits/33023"
        }
    ],
    "refs_list": [
        "http://lists.apple.com/archives/security-announce/2010//Mar/msg00001.html",
        "http://lists.opensuse.org/opensuse-security-announce/2009-07/msg00002.html",
        "http://marc.info/?l=bugtraq&m=127420533226623&w=2",
        "http://marc.info/?l=bugtraq&m=129070310906557&w=2",
        "http://marc.info/?l=bugtraq&m=133469267822771&w=2",
        "http://marc.info/?l=bugtraq&m=136485229118404&w=2",
        "http://secunia.com/advisories/35326",
        "http://secunia.com/advisories/35344",
        "http://secunia.com/advisories/35685",
        "http://secunia.com/advisories/35788",
        "http://secunia.com/advisories/37460",
        "http://secunia.com/advisories/42368",
        "http://securitytracker.com/id?1022332",
        "http://sunsolve.sun.com/search/document.do?assetkey=1-26-263529-1",
        "http://support.apple.com/kb/HT4077",
        "http://svn.apache.org/viewvc?rev=747840&view=rev",
        "http://svn.apache.org/viewvc?rev=781379&view=rev",
        "http://svn.apache.org/viewvc?rev=781382&view=rev",
        "http://tomcat.apache.org/security-4.html",
        "http://tomcat.apache.org/security-5.html",
        "http://tomcat.apache.org/security-6.html",
        "http://www.debian.org/security/2011/dsa-2207",
        "http://www.mandriva.com/security/advisories?name=MDVSA-2009:136",
        "http://www.mandriva.com/security/advisories?name=MDVSA-2009:138",
        "http://www.mandriva.com/security/advisories?name=MDVSA-2010:176"
    ]
}