GHSA-v8j6-6c2r-r27c CVE-2021-31805
Expression Language Injection in Apache Struts
- Severity
- 9.8 / 10
- Critical · CVSS 3.1
- Exploit chance (EPSS)
- 85.43%
- Chance of exploitation in the next 30 days. Higher than 99.72% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-917 Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')
- Fix
2.5.30- Upgrade org.apache.struts:struts2-core to this version or later
Description
The fix issued for CVE-2020-17530 was incomplete. So from Apache Struts 2.0.0 to 2.5.29, still some of the tag’s attributes could perform a double evaluation if a developer applied forced OGNL evaluation by using the %{...} syntax. Using forced OGNL evaluation on untrusted user input can lead to a Remote Code Execution and security degradation.
Affected versions
Maven
| Package | Vulnerable | Fixed in |
|---|---|---|
| org.apache.struts:struts2-core | >= 2.0.0, < 2.5.30 |
2.5.30 |
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.struts:struts2-core Maven → 2.5.30
- maven
<dependency><groupId>org.apache.struts</groupId><artifactId>struts2-core</artifactId><version>2.5.30</version></dependency>- gradle
implementation("org.apache.struts:struts2-core:2.5.30")
Severity breakdown
CVSS 3.1 9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Weakness
CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')
The product constructs all or part of an expression language (EL) statement in a framework such as a Java Server Page (JSP) using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended EL statement before it is executed.
How to prevent it
- Architecture and Design: Avoid adding user-controlled data into an expression interpreter when possible.
- Implementation: If user-controlled data must be added to an expression interpreter, one or more of the following should be performed: Validate that the user input will not evaluate as an expression Encode the user input in a way that ensures it is not evaluated as an expression
- System Configuration, Operation: The framework or tooling might allow the developer to disable or deactivate the processing of EL expressions, such as setting the isELIgnored attribute for a JSP page to "true".
References
Advisories
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-8c6j-ffmf-q6vm Apache Struts RCE Vulnerability | High Known exploited | Also affects org.apache.struts:struts2-core |
| GHSA-47qp-8v9g-39hp Code injection in Apache Struts | Critical Known exploited | Also affects org.apache.struts:struts2-core |
| GHSA-4wrr-9h5r-m92w Apache Struts Remote Java Code Execution | Critical Known exploited | Also affects org.apache.struts:struts2-core |
| CVE-2020-17530 Remote code execution in Apache Struts | Critical Known exploited | Also affects org.apache.struts:struts2-core |
| GHSA-j77q-2qqg-6989 Apache Struts vulnerable to remote arbitrary command execution due to improper input validation | Critical Known exploited | Also affects org.apache.struts:struts2-core |
| CVE-2018-11776 Apache Struts vulnerable to remote command execution (RCE) due to improper input validation | High Known exploited | Also affects org.apache.struts:struts2-core |
| GHSA-qcfc-hmrc-59x7 Apache Struts 2 is Missing XML Validation | High | Also affects org.apache.struts:struts2-core |
| GHSA-rg58-xhh7-mqjw Apache Struts has a Denial of Service vulnerability | High | Also affects org.apache.struts:struts2-core |
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