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.
https://www.redhat.com/archives/fedora-package-announce/2009-November/msg01246.html
https://www.redhat.com/archives/fedora-package-announce/2009-November/msg01216.html
https://www.redhat.com/archives/fedora-package-announce/2009-November/msg01156.html
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A9101
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A6628
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A18915
https://exchange.xforce.ibmcloud.com/vulnerabilities/50930
http://www.vupen.com/english/advisories/2010/3056
http://www.vupen.com/english/advisories/2009/3316
http://www.vupen.com/english/advisories/2009/1856
http://www.vupen.com/english/advisories/2009/1496
http://www.vmware.com/security/advisories/VMSA-2009-0016.html
http://www.securityfocus.com/bid/35196
http://www.securityfocus.com/archive/1/507985/100/0/threaded
http://www.securityfocus.com/archive/1/504125/100/0/threaded
http://www.securityfocus.com/archive/1/504108/100/0/threaded
http://www.securityfocus.com/archive/1/504045/100/0/threaded
http://www.mandriva.com/security/advisories?name=MDVSA-2010:176
http://www.mandriva.com/security/advisories?name=MDVSA-2009:138
http://www.mandriva.com/security/advisories?name=MDVSA-2009:136
http://www.debian.org/security/2011/dsa-2207
http://tomcat.apache.org/security-6.html
http://tomcat.apache.org/security-5.html
http://tomcat.apache.org/security-4.html
http://svn.apache.org/viewvc?rev=781382&view=rev
http://svn.apache.org/viewvc?rev=781379&view=rev
http://svn.apache.org/viewvc?rev=747840&view=rev
http://support.apple.com/kb/HT4077
http://sunsolve.sun.com/search/document.do?assetkey=1-26-263529-1
http://securitytracker.com/id?1022332
http://secunia.com/advisories/42368
http://secunia.com/advisories/37460
http://secunia.com/advisories/35788
http://secunia.com/advisories/35685
http://secunia.com/advisories/35344
http://secunia.com/advisories/35326
http://marc.info/?l=bugtraq&m=136485229118404&w=2
http://marc.info/?l=bugtraq&m=133469267822771&w=2
http://marc.info/?l=bugtraq&m=129070310906557&w=2
http://marc.info/?l=bugtraq&m=127420533226623&w=2
http://lists.opensuse.org/opensuse-security-announce/2009-07/msg00002.html
http://lists.apple.com/archives/security-announce/2010//Mar/msg00001.html