# CVE-2013-1856: activesupport Improper Input Validation vulnerability

> Remote attackers can read arbitrary files or cause denial of service via XML external entity attacks in Ruby on Rails when using JRuby.

- **Severity:** Medium 5.8 (`AV:N/AC:M/Au:N/C:P/I:N/A:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Mar 2013
- **Updated:** 6 Aug 2024
- **Also known as:** GHSA-9c2j-593q-3g82

## What is CVE-2013-1856?

CVE-2013-1856 is a medium-severity vulnerability in Rubyonrails Rails, published on 19 Mar 2013. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The ActiveSupport::XmlMini_JDOM backend in lib/active_support/xml_mini/jdom.rb in the Active Support component in Ruby on Rails 3.0.x and 3.1.x before 3.1.12 and 3.2.x before 3.2.13, when JRuby is used, does not properly restrict the capabilities of the XML parser, which allows remote attackers to read arbitrary files or cause a denial of service (resource consumption) via vectors involving (1) an external DTD or (2) an external entity declaration in conjunction with an entity reference.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2013-1856?

4 open source packages ship an affected version, including activesupport. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `activesupport` | RubyGems | From 3.0.0 | 3.1.12 |
| `activesupport` | RubyGems | From 3.0.0 | 3.1.12 |
| `activesupport` | RubyGems | From 3.2.0 | 3.2.13 |
| `activesupport` | RubyGems | From 3.2.0 | 3.2.13 |

Products: Rubyonrails Rails, Rubyonrails Ruby on Rails.

## How do I fix CVE-2013-1856?

Upgrade activesupport to a fixed version for your release line: 3.1.12 or 3.2.13.

## Is CVE-2013-1856 being exploited?

There is no known exploitation of CVE-2013-1856 in the wild and no public exploit code.

## Other vulnerabilities in Rubyonrails Rails

- [CVE-2013-0277](https://insights.sbomify.com/CVE-2013-0277/): Active Record contains deserialization of arbitrary YAML (critical 10.0)
- [CVE-2017-17916](https://insights.sbomify.com/CVE-2017-17916/): SQL injection in n/a (high 8.1)
- [CVE-2017-17917](https://insights.sbomify.com/CVE-2017-17917/): SQL injection in n/a (high 8.1)
- [CVE-2026-33195](https://insights.sbomify.com/CVE-2026-33195/): Rails Active Storage has possible Path Traversal in DiskService (high 8.0)
- [CVE-2024-26142](https://insights.sbomify.com/CVE-2024-26142/): Rails possible ReDoS vulnerability in Accept header parsing in Action Dispatch (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2013-1856 and fix it if it is affected.

What it is: CVE-2013-1856 is a medium-severity vulnerability in Rubyonrails Rails, published on 19 Mar 2013. 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-2013-1856 in the wild and no public exploit code.

Affected packages and fixed versions:
- activesupport (RubyGems): affected from 3.0.0; fixed in 3.1.12
- activesupport (RubyGems): affected from 3.0.0; fixed in 3.1.12
- activesupport (RubyGems): affected from 3.2.0; fixed in 3.2.13
- activesupport (RubyGems): affected from 3.2.0; fixed in 3.2.13

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-2013-1856/ (Markdown: https://insights.sbomify.com/CVE-2013-1856/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2013-1856
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2013-1856
- OSV: https://osv.dev/vulnerability/CVE-2013-1856

---
From sbomify Insights: https://insights.sbomify.com/CVE-2013-1856/
Summaries are generated and may contain mistakes; the official description above is the record.