---
id: CVE-2026-91018
title: "lwIP (Lightweight IP)\_has a double free vulnerability, which could crash the system, cause a DoS, memory corruption, or allow code execution on the victim system."
summary: "lwIP (Lightweight IP)\_has a double free vulnerability, which could crash the system, cause a DoS, memory corruption, or allow code execution on the victim system."
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-415
vendor: lwIP
product: lwIP API
affected:
  - api >= 2.0.1 <= 2.2.1
published: '2026-09-22'
updated: '2026-09-23'
sourceUpdated: '2026-09-23T19:42:48.540'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-91018'
references:
  - url: 'https://cgit.git.savannah.gnu.org/cgit/lwip.git'
    label: ics-cert@hq.dhs.gov
  - url: >-
      https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-265-02.json
    label: ics-cert@hq.dhs.gov
  - url: 'https://www.cisa.gov/news-events/ics-advisories/icsa-26-265-02'
    label: ics-cert@hq.dhs.gov
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-91018.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-91018'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-91018'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00397
epssPercentile: 0.33773
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-09-23T13:03:21.536853Z'
ingestedAt: '2026-09-22T21:11:40.325Z'
---

## Overview

lwIP (Lightweight IP) has a double free vulnerability, which could crash the system, cause a DoS, memory corruption, or allow code execution on the victim system.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · updated 2026-09-23 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-91018.json)