What is CVE-2026-91018?

CVE-2026-91018 is a high-severity vulnerability in Lwip API, classified under Double Free. CVSS score: 8.8/10. Published 2026-09-22.

How severe is CVE-2026-91018?

High severity. CVSS v3 base score is 8.8 out of 10.

Double Free in Lwip API

CVE-2026-91018

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.

Vulnerability class: Double Free

Published 2026-09-22.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Lwip API

Weakness classification (CWE)

CWE-415 — Double Free

References

cgit.git.savannah.gnu.org/cgit/lwip.git
www.cisa.gov/news-events/ics-advisories/icsa-26-265-02
github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-265-02.js…

Frequently asked questions

What is CVE-2026-91018?: CVE-2026-91018 is a high-severity vulnerability in Lwip API, classified under Double Free. CVSS score: 8.8/10. Published 2026-09-22.
How severe is CVE-2026-91018?: High severity. CVSS v3 base score is 8.8 out of 10.