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CVE-2013-1856 activesupport

CVE-2013-1856 is a Improper Input Validation vulnerability in activesupport. A fix is available for activesupport — see the affected versions and patch details below.

activesupport Improper Input Validation vulnerability

Published
Oct 24, 2017
Updated
Dec 5, 2024
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed
Exploitation data as of Sep 22, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
2.1%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs80th percentile — riskier than 80% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

2 pkgs affected
💎activesupport💎activesupport

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.

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.

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
💎RubyGemsactivesupport3.0.0&&< 3.1.123.1.12bundle update activesupport --conservative
💎RubyGemsactivesupport3.2.0&&< 3.2.133.2.13bundle update activesupport --conservative

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for activesupport, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update activesupport to 3.1.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2013-1856 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2013-1856 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2013-1856. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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.
O3 Security · Impact-Aware SCA

Is CVE-2013-1856 in your dependencies?

O3 Security finds CVE-2013-1856 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

CVE-2013-1856: activesupport DoS | O3 Security