Servers and applications
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 %…
- Severity
- Medium 4.3
- Published
- 5 Jun 2009
- Last changed
- 16 Jun 2026
- Added to UpHeron
- 21 Oct 2026
- Exploit chance
- 94% in the next 30 daysHigher than 99% of CVEs. EPSS by FIRST, 12 Nov 2026
- Weakness
- Information exposure (CWE-200)
- Attack
- Over the network · No login needed
- Attacker can
- Read some data
- CVSS vector
AV:N/AC:M/Au:N/C:P/I:N/A:N- Sources
- NVD
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.
Affected software
| Software | Affected versions |
|---|---|
Apache TomcatServers and applications · cpe:a:apache:tomcat |
All 87 release lines
|