High severity · published Sep 22, 2026
CVE-2026-91018
Double Free in lwIP (lightweight IP)
8.8
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 34% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LA
lwIP API · lwIP
2.0.1 through 2.2.1 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-91018
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-91018
cgit.git.savannah.gnu.org
https://cgit.git.savannah.gnu.org/cgit/lwip.git
github.com
https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-265-02.json
www.cisa.gov
https://www.cisa.gov/news-events/ics-advisories/icsa-26-265-02