postal-mime: Quadratic CPU consumption when decoding a header of many joinable RFC 2047 base64 encoded words

影響: npm:postal-mime >= 3.0.0, < 4.0.8 → 4.0.8

Decoding a header that holds a long run of joinable RFC 2047 base64 encoded words, such as =?utf-8?B?QUJD?= repeated tens of thousands of times in a Subject, From, To, a filename or a description, took time quadratic in the number of words. The join check ran a regex over the text joined so far for every word, which flattens the accumulated string each time. A single well formed message of about 1.6 MB blocked the event loop for one to twenty seconds depending on the host, and inline message/rf…

Read on GitHub Advisory Database

On 10/24/2026, 06:54 AM, GitHub Advisory Database published "postal-mime: Quadratic CPU consumption when decoding a header of many joinable RFC 2047 base64 encoded words" (type: Advisory). Severity is "High" (high). Related technologies: JavaScript / Node.js.