# CVE-2016-4431: Apache Struts Access Control Redirect

> Remote attackers can bypass access restrictions and conduct redirection attacks in Apache Struts 2 by leveraging a default method.

- **Severity:** High 7.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 Jul 2016
- **Updated:** 6 Aug 2024
- **Also known as:** GHSA-vq79-mgpx-2wx4

## What is CVE-2016-4431?

CVE-2016-4431 is a high-severity vulnerability in Apache Struts, published on 4 Jul 2016. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Apache Struts 2 2.3.20 through 2.3.28.1 allows remote attackers to bypass intended access restrictions and conduct redirection attacks by leveraging a default method.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2016-4431?

2 open source packages ship an affected version, including org.apache.struts:struts-parent. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.apache.struts:struts-parent` | Maven | From 2.3.20 | 2.3.29 |
| `org.apache.struts:struts-parent` | Maven | From 2.3.20 | 2.3.29 |

Products: Apache Struts.

## How do I fix CVE-2016-4431?

Upgrade org.apache.struts:struts-parent to 2.3.29 or later.

## Is CVE-2016-4431 being exploited?

There is no known exploitation of CVE-2016-4431 in the wild and no public exploit code.

## Other vulnerabilities in Apache Struts

- [CVE-2020-17530](https://insights.sbomify.com/CVE-2020-17530/): Apache Struts Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2017-9791](https://insights.sbomify.com/CVE-2017-9791/): Apache Struts 1 Improper Input Validation (critical 9.8, exploited in the wild)
- [CVE-2017-5638](https://insights.sbomify.com/CVE-2017-5638/): Apache Struts Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2012-0391](https://insights.sbomify.com/CVE-2012-0391/): Apache Struts 2 Improper Input Validation (critical 9.8, exploited in the wild)
- [CVE-2018-11776](https://insights.sbomify.com/CVE-2018-11776/): Apache Struts Remote Code Execution (high 8.1, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-4431 and fix it if it is affected.

What it is: CVE-2016-4431 is a high-severity vulnerability in Apache Struts, published on 4 Jul 2016. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2016-4431 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.apache.struts:struts-parent (Maven): affected from 2.3.20; fixed in 2.3.29
- org.apache.struts:struts-parent (Maven): affected from 2.3.20; fixed in 2.3.29

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2016-4431/ (Markdown: https://insights.sbomify.com/CVE-2016-4431/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-4431
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-4431
- OSV: https://osv.dev/vulnerability/CVE-2016-4431

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From sbomify Insights: https://insights.sbomify.com/CVE-2016-4431/
Summaries are generated and may contain mistakes; the official description above is the record.