CVE-2026-22737: Spring Framework Info Disclosure Bug

CVE-2026-22737 Overview

CVE-2026-22737 is a Path Traversal vulnerability affecting Spring Framework applications that utilize Java scripting engine-enabled template views such as JRuby and Jython. When exploited, this vulnerability allows attackers to disclose content from files outside the configured locations for script template views in both Spring MVC and Spring WebFlux applications.

Critical Impact

Unauthorized disclosure of sensitive file contents from outside configured template directories, potentially exposing configuration files, credentials, or other sensitive application data.

Affected Products

• Spring Framework versions 7.0.0 through 7.0.5
• Spring Framework versions 6.2.0 through 6.2.16
• Spring Framework versions 6.1.0 through 6.1.25
• Spring Framework versions 5.3.0 through 5.3.46

Discovery Timeline

• 2026-03-20 - CVE-2026-22737 published to NVD
• 2026-03-20 - Last updated in NVD database

Technical Details for CVE-2026-22737

Vulnerability Analysis

This vulnerability is classified as CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), commonly known as Path Traversal. The flaw exists in the handling of script template views within Spring MVC and Spring WebFlux frameworks when Java scripting engines like JRuby or Jython are enabled.

The vulnerability allows an attacker to craft malicious requests that traverse outside the intended template directory structure. By manipulating path parameters or view names, an attacker can access files that should not be accessible through the template rendering mechanism. This can result in the disclosure of sensitive configuration files, application source code, or other protected resources on the server filesystem.

The network-accessible nature of this vulnerability means it can be exploited remotely without requiring authentication, though the attack complexity is considered high as specific conditions must be met for successful exploitation.

Root Cause

The root cause lies in insufficient validation and sanitization of template view paths when Java scripting engines (JRuby, Jython) are enabled for template rendering. The framework fails to properly restrict path resolution, allowing directory traversal sequences to escape the configured script template view directories.

Attack Vector

The attack is conducted over the network by sending specially crafted HTTP requests to a vulnerable Spring application. An attacker manipulates view name resolution or template path parameters to include path traversal sequences (such as ../). When the application attempts to resolve and render the template, the scripting engine follows the traversal path, accessing and potentially disclosing files from unauthorized locations on the filesystem.

The vulnerability requires that the target application has Java scripting engine template views enabled (JRuby, Jython, or similar JSR-223 compliant scripting engines), which limits the scope of affected applications to those with this specific configuration.

Detection Methods for CVE-2026-22737

Indicators of Compromise

• HTTP requests containing path traversal sequences (../, ..%2f, ..%252f) in template-related parameters
• Unusual file access patterns in application logs showing attempts to read files outside template directories
• Error messages or exceptions related to file access outside configured template paths
• Access logs showing requests targeting script template endpoints with encoded directory traversal patterns

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block path traversal sequences in request parameters
• Enable verbose logging for template resolution operations to capture suspicious path requests
• Deploy intrusion detection systems (IDS) with signatures for path traversal attack patterns
• Monitor application logs for file access exceptions or security-related template rendering errors

Monitoring Recommendations

• Configure centralized log aggregation to correlate template access events across application instances
• Set up alerts for repeated failed template resolution attempts that may indicate exploitation attempts
• Monitor for unusual file read operations by the application process, particularly outside application directories
• Implement real-time security monitoring for Spring Framework applications with scripting engine templates enabled

How to Mitigate CVE-2026-22737

Immediate Actions Required

• Upgrade Spring Framework to patched versions: 7.0.6+, 6.2.17+, 6.1.26+, or 5.3.47+
• If immediate patching is not possible, disable Java scripting engine template views (JRuby, Jython) temporarily
• Review application configurations to identify components using script template views
• Implement input validation at the application layer to reject path traversal sequences

Patch Information

Spring has released security patches addressing this vulnerability. Organizations should upgrade to the following fixed versions:

• Spring Framework 7.0.6 or later for the 7.x branch
• Spring Framework 6.2.17 or later for the 6.2.x branch
• Spring Framework 6.1.26 or later for the 6.1.x branch
• Spring Framework 5.3.47 or later for the 5.3.x branch

For detailed patch information, refer to the Spring Security Advisory for CVE-2026-22737.

Workarounds

• Disable JRuby, Jython, or other JSR-223 scripting engine template views if not required for application functionality
• Implement strict input validation on any user-controllable input that influences template view resolution
• Deploy WAF rules to block requests containing path traversal patterns targeting the application
• Restrict filesystem permissions for the application process to limit the impact of potential file disclosure

# Configuration example - Restrict template view locations in Spring configuration
# application.properties or application.yml

# Disable script template views if not needed
spring.mvc.view.prefix=/WEB-INF/views/
spring.mvc.view.suffix=.html

# If using script templates, ensure strict path configuration
# and implement custom view resolver with path validation