Review reviewCritical

CVE-2026-59083

Apache Software Foundation Apache Tomcat, tomcat

Improper Handling of URL Encoding (Hex Encoding) vulnerability in Apache Tomcat's rewrite valve allowed security constraint bypass for some configurations. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.23, from 10.1.0-M1 through 10.1.56, from 9.0.0.M1 through 9.0.119, from 8.5.0 through 8.5.100. Other versions that have reached end of support may also be affected. Users are recommended to upgrade to version 11.0.24, 10.1.57 or 9.0.120, which fix the issue.

CVSS: 9.1
EPSS: 0.38%
CISA KEV: Not listed
Published: 2026.07.14

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.38%

Technical severityCVSS 9.1

Vulnerability overview

Affected product and versions

Product: Apache Software Foundation Apache Tomcat, tomcat
Affected versions: >= 11.0.0-M1 <= 11.0.23, >= 10.1.0-M1 <= 10.1.56, >= 9.0.0.M1 <= 9.0.119, >= 8.5.0 <= 8.5.100, <= 8.0.0, >= 9.0.0 <= 9.0.119, >= 10.1.0 <= 10.1.56, >= 11.0.0 <= 11.0.23
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that Apache Software Foundation Apache Tomcat, tomcat and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE: CWE-177