{"id":"CVE-2026-27492","aliases":["GHSA-49pc-8936-wvfp"],"url":"https://o3.security/vulnerability/CVE-2026-27492","summary":"Lettermint Node.js SDK leaks email properties to unintended recipients when client instance is reused","details":"### Impact\nEmail 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.\n\n### Patches\nYes, the issue has been patched. Users should upgrade to v1.5.1 or later.\n\n### Workarounds\nIf upgrading immediately is not possible, instantiate a new client for each send:\n```js\nconst client = new Lettermint({ apiKey: process.env.LETTERMINT_API_KEY });\nawait client.email.to('...').subject('...').html('...').send();\n```\n\nThis ensures no state is carried over between sends.","published":"2026-02-21T10:16:03.913Z","modified":"2026-08-12T03:51:14.274324277Z","cvss":{"score":4.7,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N"},"epss":{"score":0.00166,"percentile":0.06179,"asOf":"2026-09-16"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"lettermint","fixedVersion":"1.5.1"}],"fix":{"url":"https://github.com/lettermint/lettermint-node/commit/24a17acbc2429c5eb30391f9df3dc0ea7aaf4de1","label":"lettermint/lettermint-node@24a17ac"},"references":[{"type":"WEB","url":"https://github.com/lettermint/lettermint-node/blob/main/CHANGELOG.md#151-2026-02-20"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27492.json"},{"type":"ADVISORY","url":"https://github.com/lettermint/lettermint-node/security/advisories/GHSA-49pc-8936-wvfp"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27492"},{"type":"FIX","url":"https://github.com/lettermint/lettermint-node/commit/24a17acbc2429c5eb30391f9df3dc0ea7aaf4de1"},{"type":"PACKAGE","url":"https://github.com/lettermint/lettermint-node"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:14.274324277Z"}}