Vulnerability · Published May 12, 2026 · Assigned by apache
CVE-2026-43513Apache Tomcat: LockOutRealm treats user names as case-sensitive
High 7.5
In plain English
A high-severity security flaw in Apache Tomcat from Apache Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.5%top 56.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Improper Handling of Case Sensitivity vulnerability in LockOutRealm in Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.21, from 10.1.0-M1 through 10.1.54, from 9.0.0.M1 through 9.0.117, from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Older unsupported versions may also be affected. Users are recommended to upgrade to version 11.0.22, 10.1.55 or 9.0.118 which fix the issue.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | tomcat | 1:10.1.49-4.el10_2.alma.1 | ALSA-2026:69259 |
| AlmaLinux:8 | tomcat | 1:9.0.120-1.el8_10 | ALSA-2026:68677 |
| AlmaLinux:9 | tomcat | 1:9.0.120-2.el9_8 | ALSA-2026:68660 |
| AlmaLinux:10 | tomcat-admin-webapps | 1:10.1.49-4.el10_2.alma.1 | ALSA-2026:69259 |
| AlmaLinux:8 | tomcat-admin-webapps | 1:9.0.120-1.el8_10 | ALSA-2026:68677 |
| AlmaLinux:9 | tomcat-admin-webapps | 1:9.0.120-2.el9_8 | ALSA-2026:68660 |
| AlmaLinux:10 | tomcat-docs-webapp | 1:10.1.49-4.el10_2.alma.1 | ALSA-2026:69259 |
| AlmaLinux:8 | tomcat-docs-webapp | 1:9.0.120-1.el8_10 | ALSA-2026:68677 |
| AlmaLinux:9 | tomcat-docs-webapp | 1:9.0.120-2.el9_8 | ALSA-2026:68660 |
| AlmaLinux:8 | tomcat-el-3.0-api | 1:9.0.120-1.el8_10 | ALSA-2026:68677 |
| AlmaLinux:9 | tomcat-el-3.0-api | 1:9.0.120-2.el9_8 | ALSA-2026:68660 |
| AlmaLinux:10 | tomcat-el-5.0-api | 1:10.1.49-4.el10_2.alma.1 | ALSA-2026:69259 |
| AlmaLinux:8 | tomcat-jsp-2.3-api | 1:9.0.120-1.el8_10 | ALSA-2026:68677 |
| AlmaLinux:9 | tomcat-jsp-2.3-api | 1:9.0.120-2.el9_8 | ALSA-2026:68660 |
| AlmaLinux:10 | tomcat-jsp-3.1-api | 1:10.1.49-4.el10_2.alma.1 | ALSA-2026:69259 |
| AlmaLinux:10 | tomcat-lib | 1:10.1.49-4.el10_2.alma.1 | ALSA-2026:69259 |
| AlmaLinux:8 | tomcat-lib | 1:9.0.120-1.el8_10 | ALSA-2026:68677 |
| AlmaLinux:9 | tomcat-lib | 1:9.0.120-2.el9_8 | ALSA-2026:68660 |
| AlmaLinux:8 | tomcat-servlet-4.0-api | 1:9.0.120-1.el8_10 | ALSA-2026:68677 |
| AlmaLinux:9 | tomcat-servlet-4.0-api | 1:9.0.120-2.el9_8 | ALSA-2026:68660 |
| AlmaLinux:10 | tomcat-servlet-6.0-api | 1:10.1.49-4.el10_2.alma.1 | ALSA-2026:69259 |
| AlmaLinux:10 | tomcat-webapps | 1:10.1.49-4.el10_2.alma.1 | ALSA-2026:69259 |
| AlmaLinux:8 | tomcat-webapps | 1:9.0.120-1.el8_10 | ALSA-2026:68677 |
| AlmaLinux:9 | tomcat-webapps | 1:9.0.120-2.el9_8 | ALSA-2026:68660 |
| AlmaLinux:10 | tomcat9 | 1:9.0.120-1.el10_2.alma.1 | ALSA-2026:68651 |
| AlmaLinux:10 | tomcat9-admin-webapps | 1:9.0.120-1.el10_2.alma.1 | ALSA-2026:68651 |
| AlmaLinux:10 | tomcat9-docs-webapp | 1:9.0.120-1.el10_2.alma.1 | ALSA-2026:68651 |
| AlmaLinux:10 | tomcat9-el-3.0-api | 1:9.0.120-1.el10_2.alma.1 | ALSA-2026:68651 |
| AlmaLinux:10 | tomcat9-jsp-2.3-api | 1:9.0.120-1.el10_2.alma.1 | ALSA-2026:68651 |
| AlmaLinux:10 | tomcat9-lib | 1:9.0.120-1.el10_2.alma.1 | ALSA-2026:68651 |
| AlmaLinux:10 | tomcat9-servlet-4.0-api | 1:9.0.120-1.el10_2.alma.1 | ALSA-2026:68651 |
| AlmaLinux:10 | tomcat9-webapps | 1:9.0.120-1.el10_2.alma.1 | ALSA-2026:68651 |
| Debian:12 | tomcat10 | 10.1.55-1~deb12u1 | DEBIAN-CVE-2026-43513 |
| Debian:13 | tomcat10 | 10.1.55-1~deb13u1 | DEBIAN-CVE-2026-43513 |
| Debian:14 | tomcat10 | 10.1.55-1 | DEBIAN-CVE-2026-43513 |
| Debian:13 | tomcat11 | 11.0.22-1~deb13u1 | DEBIAN-CVE-2026-43513 |
| Debian:14 | tomcat11 | 11.0.22-1 | DEBIAN-CVE-2026-43513 |
| Debian:12 | tomcat9 | 9.0.70-2 | DEBIAN-CVE-2026-43513 |
| Debian:13 | tomcat9 | 9.0.70-2 | DEBIAN-CVE-2026-43513 |
| Debian:14 | tomcat9 | 9.0.70-2 | DEBIAN-CVE-2026-43513 |
| Maven | org.apache.tomcat.embed:tomcat-embed-core | 9.0.118 | GHSA-5mp6-jrq3-r938 |
| Maven | org.apache.tomcat.embed:tomcat-embed-core | 10.1.55 | GHSA-5mp6-jrq3-r938 |
| Maven | org.apache.tomcat.embed:tomcat-embed-core | 11.0.22 | GHSA-5mp6-jrq3-r938 |
| Maven | org.apache.tomcat:tomcat | 9.0.118 | GHSA-5mp6-jrq3-r938 |
| Maven | org.apache.tomcat:tomcat | 11.0.22 | GHSA-5mp6-jrq3-r938 |
| Maven | org.apache.tomcat:tomcat | 10.1.55 | GHSA-5mp6-jrq3-r938 |
| Maven | org.apache.tomcat:tomcat-catalina | 9.0.118 | GHSA-5mp6-jrq3-r938 |
| Maven | org.apache.tomcat:tomcat-catalina | 10.1.55 | GHSA-5mp6-jrq3-r938 |
| Maven | org.apache.tomcat:tomcat-catalina | 11.0.22 | GHSA-5mp6-jrq3-r938 |
| Rocky Linux:10 | tomcat | 1:10.1.49-4.el10_2 | RLSA-2026:69259 |
| Rocky Linux:8 | tomcat | 1:9.0.120-1.el8_10 | RLSA-2026:68677 |
| Rocky Linux:9 | tomcat | 1:9.0.120-2.el9_8 | RLSA-2026:68660 |
| Rocky Linux:10 | tomcat9 | 1:9.0.120-1.el10_2 | RLSA-2026:68651 |
| Ubuntu:25.10 | tomcat10 | 10.1.40-1ubuntu1.25.10.1 | UBUNTU-CVE-2026-43513 |
| Ubuntu:26.04:LTS | tomcat10 | 10.1.40-1ubuntu1.26.04.1 | UBUNTU-CVE-2026-43513 |
| Ubuntu:25.10 | tomcat11 | no fix listed | UBUNTU-CVE-2026-43513 |
| Ubuntu:26.04:LTS | tomcat11 | no fix listed | UBUNTU-CVE-2026-43513 |
| Ubuntu:25.10 | tomcat9 | 9.0.95-1ubuntu1.1 | UBUNTU-CVE-2026-43513 |
| Ubuntu:26.04:LTS | tomcat9 | 9.0.115-1ubuntu0.1 | UBUNTU-CVE-2026-43513 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Apache Software Foundation | Apache Tomcat | 11.0.0-M1 – through 11.0.2110.1.0-M1 – through 10.1.549.0.0.M1 – through 9.0.1178.5.0 – through 8.5.1007.0.0 – through 7.0.109 |
Weakness: CWE-178 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N