GHSA-5mp6-jrq3-r938 BIT-tomcat-2026-43513 CVE-2026-43513
Apache Tomcat: LockOutRealm treats user names as case-sensitive
High
Maven
- Severity
- 7.5 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- 0.50%
- Chance of exploitation in the next 30 days. Higher than 43.04% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-178 Improper Handling of Case Sensitivity
- Fix
- Available
- 3 packages have a fixed version
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 versions
Maven
| Package | Vulnerable | Fixed in |
|---|---|---|
| org.apache.tomcat.embed:tomcat-embed-core | < 9.0.118 |
9.0.118 |
| org.apache.tomcat.embed:tomcat-embed-core | >= 10.1.0-M1, < 10.1.55 |
10.1.55 |
| org.apache.tomcat.embed:tomcat-embed-core | >= 11.0.0-M1, < 11.0.22 |
11.0.22 |
| org.apache.tomcat:tomcat | < 9.0.118 |
9.0.118 |
| org.apache.tomcat:tomcat | >= 10.1.0-M1, < 10.1.55 |
10.1.55 |
| org.apache.tomcat:tomcat | >= 11.0.0-M1, < 11.0.22 |
11.0.22 |
| org.apache.tomcat:tomcat-catalina | < 9.0.118 |
9.0.118 |
| org.apache.tomcat:tomcat-catalina | >= 10.1.0-M1, < 10.1.55 |
10.1.55 |
| org.apache.tomcat:tomcat-catalina | >= 11.0.0-M1, < 11.0.22 |
11.0.22 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
org.apache.tomcat.embed:tomcat-embed-core Maven → 9.0.118
- maven
<dependency><groupId>org.apache.tomcat.embed</groupId><artifactId>tomcat-embed-core</artifactId><version>9.0.118</version></dependency>- gradle
implementation("org.apache.tomcat.embed:tomcat-embed-core:9.0.118")
org.apache.tomcat:tomcat Maven → 9.0.118
- maven
<dependency><groupId>org.apache.tomcat</groupId><artifactId>tomcat</artifactId><version>9.0.118</version></dependency>- gradle
implementation("org.apache.tomcat:tomcat:9.0.118")
org.apache.tomcat:tomcat-catalina Maven → 9.0.118
- maven
<dependency><groupId>org.apache.tomcat</groupId><artifactId>tomcat-catalina</artifactId><version>9.0.118</version></dependency>- gradle
implementation("org.apache.tomcat:tomcat-catalina:9.0.118")
Severity breakdown
CVSS 3.1 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Weakness
CWE-178: Improper Handling of Case Sensitivity
The product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.
How to prevent it
- Architecture and Design: Avoid making decisions based on names of resources (e.g. files) if those resources can have alternate names.
- Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
- Implementation: Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
References
Advisories
Packages
Other links
- github.com/apache/tomcat/commit/4a90d3fa93988c447cd5bb7482f76ff70d7f15c2
- github.com/apache/tomcat/commit/6dd75beb55bd42fc5f78e929596b25018cd17717
- github.com/apache/tomcat/commit/83f3e51df7b87f5f6e626951c575ded1a512e8ef
- lists.apache.org/thread/ytjcgldshj73lcnd1sh95od5hrghwogp
- tomcat.apache.org/security-10.html
- tomcat.apache.org/security-11.html
- tomcat.apache.org/security-9.html
- openwall.com/lists/oss-security/2026/05/12/9
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-69r9-qgr7-g2wj Apache Tomcat Missing Encryption of Sensitive Data vulnerability | High Known exploited | Also affects org.apache.tomcat:tomcat |
| GHSA-83qj-6fr2-vhqg Apache Tomcat: Potential RCE and/or information disclosure and/or information corruption with partial PUT | Critical Known exploited | Also affects org.apache.tomcat.embed:tomcat-embed-core |
| GHSA-qppj-fm5r-hxr3 HTTP/2 Stream Cancellation Attack | Medium Known exploited | Also affects org.apache.tomcat.embed:tomcat-embed-core |
| GHSA-xjgh-84hx-56c5 Unrestricted Upload of File with Dangerous Type Apache Tomcat | High Known exploited | Also affects org.apache.tomcat.embed:tomcat-embed-core |
| GHSA-cw54-59pw-4g8c Apache Tomcat Improper Access Control vulnerability | Critical Known exploited | Also affects org.apache.tomcat:tomcat-catalina |
| CVE-2020-1938 Improper Privilege Management in Tomcat | Critical Known exploited | Also affects org.apache.tomcat.embed:tomcat-embed-core |
| GHSA-pjfr-qf3p-3q25 When running Apache Tomcat on Windows with HTTP PUTs enabled it was possible to upload a JSP file to the server | High Known exploited | Also affects org.apache.tomcat.embed:tomcat-embed-core |
| GHSA-h3x4-894j-xpx5 Apache Tomcat's FORM authentication process has an Incorrect Authorization vulnerability | Critical | Also affects org.apache.tomcat.embed:tomcat-embed-core |
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