Vulnerability in Lettermint
CVE-2026-27492
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.
EPSS: 0.002 (6.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 4.7 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N.
Affected products
- Lettermint
- Lettermint Lettermint-node — versions < 1.5.1
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Mitigation, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-27492?
- CVE-2026-27492 is a medium-severity vulnerability in Lettermint, classified under CWE-488. CVSS score: 4.7/10. Published 2026-02-21.
- How severe is CVE-2026-27492?
- Medium severity. CVSS v3 base score is 4.7 out of 10.