CVE-2026-110871

Nodemailer's address parser parses comma-separated addresses in quadratic time (O(n²)) in the number of addresses. A single crafted address string (e.g., To, Cc, Bcc, From, Reply-To) can cause significant slowdown.

Nodemailer's SMTP client response parser reassembles multiline server replies by appending each continuation line onto a single response-queue entry and re-testing whether it is still a partial reply on every line. The partial-response test performs string operations per line, which can lead to inefficient processing.

In nodemailer v9.0.0, the message-level `raw` option bypasses `disableFileAccess` and `disableUrlAccess` protections, enabling arbitrary file reads and full SSRF (Server-Side Request Forgery) in the sent message.

A vulnerability in Nodemailer allows bypassing the `disableFileAccess` and `disableUrlAccess` options when using `jsonTransport`. While the normal MIME streaming path enforces these restrictions, `jsonTransport` serializes the message in a way that bypasses them, potentially enabling access to local files or external URLs.

Nodemailer disables TLS certificate verification in its internal HTTPS fetch client by setting rejectUnauthorized: false in lib/fetch/index.js. This causes OAuth2 token requests to trust invalid or self-signed HTTPS certificates.

A vulnerability exists in the nodemailer package (npm) affecting versions from 2.7.2 to 10.0.1. Details are not fully described in the provided snippet, but vulnerable versions are confirmed.

A vulnerability in the Nodemailer library allows header injection via the `list.*.comment` field, which is not sanitized for CR (`\r`) and LF (`\n`) characters. An attacker can supply a malicious value in this field, leading to email header spoofing.

Nodemailer's SMTP client applies four regular expressions to a peer's EHLO response to detect supported SASL mechanisms. Each pattern uses overlapping whitespace-matching sub-patterns, producing quadratic (O(n^2)) backtracking on long mechanism names.

Nodemailer's address parser has three published, patched fixes for RFC 5322 comment handling inside an addr-spec. The description covers earlier issues with glued domain atoms and quoted local parts, plus related ReDoS fixes.

Nodemailer's disableFileAccess/disableUrlAccess options are a security sandbox that forbids untrusted message content from reading local files or making outbound HTTP(S) requests. The fix for GHSA-wqvq-jvpq-h66f may be incomplete, allowing bypass of the sandbox.