Vulnerability · Published Sep 22, 2026 · Assigned by icscert
CVE-2026-91018Double Free in lwIP (lightweight IP)
High 8.8
In plain English
A high-severity double free in lwIP API from lwIP. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 34% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)8.8High
Exploit odds (30 days)0.4%top 65.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | lwip | no fix listed | DEBIAN-CVE-2026-91018 |
| Debian:13 | lwip | no fix listed | DEBIAN-CVE-2026-91018 |
| Debian:14 | lwip | 2.2.1+dfsg1-8 | DEBIAN-CVE-2026-91018 |
| Ubuntu:26.10 | lwip | no fix listed | UBUNTU-CVE-2026-91018 |
Affected products (as reported)
Weakness: CWE-415 · Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H