CVE-2026-27492 Lettermint Node.js SDK leaks email properties to unintended recipients when client instance is reused
Reusing a client instance leaks previous email properties to unintended recipients, exposing sensitive data in transactional flows.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-27492?
CVE-2026-27492 is a medium-severity vulnerability in lettermint-node, published on 21 Feb 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Lettermint Node.js SDK is the official Node.js SDK for Lettermint. In versions 1.5.0 and below, email properties (such as to, subject, html, text, and attachments) are not reset between sends when a single client instance is reused across multiple .send() calls. This can cause properties from a previous send to leak into a subsequent one, potentially delivering content or recipient addresses to unintended parties. Applications sending emails to different recipients in sequence — such as transactional flows like password resets or notifications — are affected. This issue has been fixed in version 1.5.1.
Weakness: CWE-488
Which versions are affected by CVE-2026-27492?
2 open source packages ship an affected version, including lettermint. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
lettermint npm | All versions | 1.5.1 |
lettermint npm | All versions | 1.5.1 |
Products include Lettermint Lettermint.
How do I fix CVE-2026-27492?
Upgrade lettermint to 1.5.1 or later.
Is CVE-2026-27492 being exploited?
There is no known exploitation of CVE-2026-27492 in the wild and no public exploit code.
Sources
Also known as GHSA-49pc-8936-wvfp.