CVE-2026-91018: Double Free in lwIP (lightweight IP)
Awaiting analysis
AliasesUBUNTU-CVE-2026-91018DEBIAN-CVE-2026-91018
Published 22-09-2026Last modified 23-09-2026
Vulnerability summary
CVE-2026-91018 is a high (CVSS 8.8) Double Free vulnerability in lwip lwip api. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 14.3% of scored vulnerabilities.
CVSS score
8.8/10
010
High · v3.1 (CVE.org)EPSS score
0.24%
0%100%
Low · Change unavailableKEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded
Timeline
- 22-09-2026PublishedVulnerability first disclosed.
- 23-09-2026Last modifiedVulnerability information updated.
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 metrics
7 scores · 4 sources · 2 versionsHigh 8.7Preferred score · CVE.org (CNA)
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NSourcesAll 4 agree
- OSV · UbuntuEcosystem advisory · calculated8.7HighCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- OSV · DebianEcosystem advisory · calculated8.7HighCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- NVDNIST8.7HighCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
High 8.8Preferred score · CVE.org (CNA)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSourcesAll 3 agree
- OSV · UbuntuEcosystem advisory · calculated8.8HighCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- NVDNIST8.8HighCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.24%
Chance of exploitation in the next 30 days
Percentile
14%
Versus all other CVEs
30-day change
Change unavailable
Change unavailable
23-09-202622-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Debian1 product
- lwipAll versions (No fix recorded) | < 2.2.1+dfsg1-8
Lwip1 product
- lwip api≥ 2.0.1, ≤ 2.2.1
Ubuntu1 product
- lwipAll versions (No fix recorded)
3 vendors · 3 products
