{"schemaVersion":3,"id":"CVE-2026-5680","aliases":["UBUNTU-CVE-2026-5680","DEBIAN-CVE-2026-5680"],"status":"published","duplicateOf":null,"title":null,"description":"A flaw was found in Undertow. A remote attacker could exploit this vulnerability by sending specially crafted WebSocket messages with permessage-deflate negotiated. This could lead to excessive memory consumption due to the PerMessageDeflateFunction.largerBuffer() method using exponential doubling, resulting in a Denial of Service (DoS) for the affected application.","dates":{"published":"2026-08-27T16:25:29.103Z","modified":"2026-10-14T15:47:55.560Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":7.5,"severity":"high","version":"3.1","versionLabel":"v3.1","source":"CVE.org","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":7.5,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Ubuntu","score":7.5,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","exploitability":10,"impact":6,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Debian","score":7.5,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","exploitability":10,"impact":6,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":7.5,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.01096,"percentile":0.65081,"severity":"low","asOf":"2026-10-19T00:00:00.000Z","change":{"pp":0.692,"baselineDate":"2026-09-19T00:00:00.000Z","baselineScore":0.00404},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00576,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.01096,"percentile":0.65081}],"last30":[{"date":"2026-09-19T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00576,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.01096,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.01096,"percentile":0.65081}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[],"exploitCount":0,"weaknesses":[{"id":"CWE-770","name":"Allocation of Resources Without Limits or Throttling","description":"The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.","type":"weakness","status":"Incomplete","abstraction":"Base","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/770.html"}],"affected":[{"vendor":"debian","product":"undertow","name":"undertow","label":"undertow","ecosystem":"Debian","cpePart":null,"purl":"pkg:deb/debian/undertow","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null}],"versionsText":"All versions (No fix recorded)","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"undertow","name":"undertow","label":"undertow","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/undertow","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null}],"versionsText":"All versions (No fix recorded)","eol":null,"hubHref":null}],"affectedCount":2,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://access.redhat.com/errata/RHSA-2026:70228","label":"access.redhat.com/errata/RHSA-2026:70228","hostname":"access.redhat.com","tags":["Vendor Advisory","X Refsource REDHAT"]},{"url":"https://access.redhat.com/errata/RHSA-2026:70229","label":"access.redhat.com/errata/RHSA-2026:70229","hostname":"access.redhat.com","tags":["Vendor Advisory","X Refsource REDHAT"]},{"url":"https://access.redhat.com/errata/RHSA-2026:70230","label":"access.redhat.com/errata/RHSA-2026:70230","hostname":"access.redhat.com","tags":["Vendor Advisory","X Refsource REDHAT"]},{"url":"https://access.redhat.com/errata/RHSA-2026:70277","label":"access.redhat.com/errata/RHSA-2026:70277","hostname":"access.redhat.com","tags":["Vendor Advisory","X Refsource REDHAT"]},{"url":"https://access.redhat.com/security/cve/CVE-2026-5680","label":"access.redhat.com/security/cve/CVE-2026-5680","hostname":"access.redhat.com","tags":["VDB Entry","X Refsource REDHAT","REPORT"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2455350","label":"bugzilla.redhat.com/show_bug.cgi?id=2455350","hostname":"bugzilla.redhat.com","tags":["Issue Tracking","X Refsource REDHAT","REPORT"]},{"url":"https://ubuntu.com/security/CVE-2026-5680","label":"ubuntu.com/security/CVE-2026-5680","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-5680","label":"www.cve.org/CVERecord?id=CVE-2026-5680","hostname":"www.cve.org","tags":["REPORT"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-5680","label":"security-tracker.debian.org/tracker/CVE-2026-5680","hostname":"security-tracker.debian.org","tags":["Advisory"]}],"lineage":{"upstream":[],"downstream":["RHSA-2026:70228","RHSA-2026:70229","RHSA-2026:70230"],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2026-08-27T16:25:29.103Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-10-14T15:47:55.560Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":30,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-19T23:27:53.617Z","stale":false,"partial":false}}