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

- 種別: advisory
- 重大度: high
- 関連技術: nodejs
- 公開日時: 2026-10-23T21:54:36.000Z
- 情報源: GitHub Advisory Database (https://github.com/advisories/GHSA-f2hq-32vh-53cc)
- パーマリンク: https://vulnpulse.app/items/ghsa-ghsa-f2hq-32vh-53cc

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…