---
id: CVE-2026-15340
title: >-
  lwIP SMTP client does not check the size of inputs, potentially allowing a
  buffer overflow.
summary: >-
  lwIP SMTP client does not check the size of inputs, potentially allowing a
  buffer overflow.
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-120
published: '2026-10-09'
updated: '2026-10-09'
sourceUpdated: '2026-10-09T17:29:33.410'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-15340'
references:
  - url: >-
      https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-279-02.json
    label: ics-cert@hq.dhs.gov
  - url: 'https://www.cisa.gov/news-events/ics-advisories/icsa-26-279-02'
    label: ics-cert@hq.dhs.gov
tags:
  - nvd
ingestedAt: '2026-10-09T16:02:33.386Z'
---

## Overview

lwIP SMTP client does not check the size of inputs, potentially allowing a buffer overflow.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.