CVE-2024-3651: Denial of Service via Quadratic Complexity in kjd/idna

Impact A specially crafted argument to the idna.encode() function could consume significant resources. This may lead to a denial-of-service.

Patches The function has been refined to reject such strings without the associated resource consumption in version 3.7.

Workarounds Domain names cannot exceed 253 characters in length, if this length limit is enforced prior to passing the domain to the idna.encode() function it should no longer consume significant resources. This is triggered by arbitrarily large inputs that would not occur in normal usage, but may be passed to the library assuming there is no preliminary input validation by the higher-level application.

References https://huntr.com/bounties/93d78d07-d791-4b39-a845-cbfabc44aadb

— GitHub

A specially crafted argument to the idna.encode() function could consume significant resources. This may lead to a denial-of-service.

Reference: https://github.com/kjd/idna/security/advisories/GHSA-jjg7-2v4v-x38h

— Red Hat

A vulnerability was identified in the kjd/idna library, specifically within the idna.encode() function, affecting version 3.6. The issue arises from the function's handling of crafted input strings, which can lead to quadratic complexity and consequently, a denial of service condition. This vulnerability is triggered by a crafted input that causes the idna.encode() function to process the input with considerable computational load, significantly increasing the processing time in a quadratic manner relative to the input size.

— NVD