{"id":"CVE-2026-91018","state":"PUBLISHED","title":"Double Free in lwIP (lightweight IP)","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.","publishedAt":"2026-09-22T20:25:33.530Z","updatedAt":"2026-09-23T13:05:15.963Z","severity":{"score":8.7,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","source":"icscert"},"assigner":"icscert","products":["lwIP lwIP API"],"affected":[{"vendor":"lwIP","product":"lwIP API","defaultStatus":"unaffected","versions":[{"version":"2.0.1","status":"affected","lessThanOrEqual":"2.2.1","versionType":"custom"}]}],"references":["https://cgit.git.savannah.gnu.org/cgit/lwip.git","https://www.cisa.gov/news-events/ics-advisories/icsa-26-265-02","https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-265-02.json"],"weaknesses":["CWE-415"],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/91xxx/CVE-2026-91018.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-91018","state":"PUBLISHED","datePublished":"2026-09-22T20:25:33.530Z","dateUpdated":"2026-09-23T13:05:15.963Z","assignerShortName":"icscert","assignerOrgId":"7d14cffa-0d7d-4270-9dc0-52cabd5a23a6","dateReserved":"2026-09-14T16:40:45.500Z"},"containers":{"cna":{"title":"Double Free in lwIP (lightweight IP)","descriptions":[{"lang":"en","value":"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":[{"vendor":"lwIP","product":"lwIP API","defaultStatus":"unaffected","versions":[{"version":"2.0.1","status":"affected","lessThanOrEqual":"2.2.1","versionType":"custom"}]}],"references":[{"url":"https://cgit.git.savannah.gnu.org/cgit/lwip.git"},{"url":"https://www.cisa.gov/news-events/ics-advisories/icsa-26-265-02"},{"url":"https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-265-02.json"}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","attackVector":"ADJACENT_NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH","baseSeverity":"HIGH","baseScore":8.8,"vectorString":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}},{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"ADJACENT","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"HIGH","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"HIGH","baseScore":8.7,"vectorString":"CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-415","lang":"en","description":"CWE-415 Double free","type":"CWE"}]}],"providerMetadata":{"shortName":"icscert","orgId":"7d14cffa-0d7d-4270-9dc0-52cabd5a23a6","dateUpdated":"2026-09-22T20:25:33.530Z"},"datePublic":"2026-09-22T17:53:00.000Z","solutions":[{"lang":"en","value":"Users of lwIP are encouraged to update their version of lwIP using the repository found at  https://cgit.git.savannah.gnu.org/cgit/lwip.git . The commit identifier that contains the fix is f873b6295933e4149a2132adf3e9a2d2a676a5ec.","supportingMedia":[{"type":"text/html","base64":false,"value":"Users of lwIP are encouraged to update their version of lwIP using the repository found at&nbsp;<a href=\"https://cgit.git.savannah.gnu.org/cgit/lwip.git\">https://cgit.git.savannah.gnu.org/cgit/lwip.git</a>. The commit identifier that contains the fix is f873b6295933e4149a2132adf3e9a2d2a676a5ec."}]}],"credits":[{"lang":"en","value":"Eric Evenchick of Tetrel Security reported this vulnerability to CISA.","type":"finder"}],"source":{"advisory":"ICSA-26-265-02","discovery":"EXTERNAL"},"x_generator":{"engine":"Vulnogram 1.0.5"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-23T13:03:21.536853Z","id":"CVE-2026-91018","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-23T13:05:15.963Z"}}]}}}