CVE-2011-5036 Rack Gem Subject to Denial of Service via Hash Collisions

What is CVE-2011-5036?

CVE-2011-5036 is a medium-severity denial of service vulnerability in n/a, published on 30 Dec 2011. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Rack before 1.1.3, 1.2.x before 1.2.5, and 1.3.x before 1.3.6 computes hash values for form parameters without restricting the ability to trigger hash collisions predictably, which allows remote attackers to cause a denial of service (CPU consumption) by sending many crafted parameters.

Weakness: CWE-310

Which versions are affected by CVE-2011-5036?

8 open source packages ship an affected version, including rack and org.jruby:jruby-parent. It affects 1 product.

Products include Rack Project Rack.

How do I fix CVE-2011-5036?

Upgrade rack to a fixed version for your release line: 1.1.3, 1.2.5 or 1.3.6.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2011-5036 being exploited?

There is no known exploitation of CVE-2011-5036 in the wild and no public exploit code.

Other vulnerabilities in n/a

• CVE-2018-16470 Rack vulnerable to Denial of Service High 7.5
• CVE-2013-0263 Rack arbitrary code execution via timing attack Medium 5.1
• CVE-2013-0183 Rack rubygems receiving excessively long lines triggers out-of-memory error Medium 5.0
• CVE-2012-6109 Rack vulnerable to REDoS Medium 4.3
• CVE-2013-0184 Rack vulnerable to Denial of Service Medium 4.3

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2011-5036, GHSA-v6j3-7jrw-hq2p.