Summary
A ReDoS vulnerability occurs when nodemailer tries to parse img files with the parameter attachDataUrls set, causing the stuck of event loop.
Another flaw was found when nodemailer tries to parse an attachments with a embedded file, causing the stuck of event loop.
Details
Regex: /^data:((?:[^;];)(?:[^,])),(.)$/
Path: compile -> getAttachments -> _processDataUrl
Regex: /(<img\b[^>]* src\s*=[\s"']*)(data:([^;]+);[^"'>\s]+)/
Path: _convertDataImages
PoC
https://gist.github.com/francoatmega/890dd5053375333e40c6fdbcc8c58df6
https://gist.github.com/francoatmega/9aab042b0b24968d7b7039818e8b2698
Impact
ReDoS causes the event loop to stuck a specially crafted evil email can cause this problem.
francoatmega Reporter
Summary
A ReDoS vulnerability occurs when nodemailer tries to parse img files with the parameter
attachDataUrlsset, causing the stuck of event loop.Another flaw was found when nodemailer tries to parse an attachments with a embedded file, causing the stuck of event loop.
Details
Regex: /^data:((?:[^;];)(?:[^,])),(.)$/
Path: compile -> getAttachments -> _processDataUrl
Regex: /(<img\b[^>]* src\s*=[\s"']*)(data:([^;]+);[^"'>\s]+)/
Path: _convertDataImages
PoC
https://gist.github.com/francoatmega/890dd5053375333e40c6fdbcc8c58df6
https://gist.github.com/francoatmega/9aab042b0b24968d7b7039818e8b2698
Impact
ReDoS causes the event loop to stuck a specially crafted evil email can cause this problem.