{"api_version":"1","generated_at":"2026-11-03T19:49:30+00:00","cve":"CVE-2026-91920","urls":{"html":"https://cve.report/CVE-2026-91920","api":"https://cve.report/api/cve/CVE-2026-91920.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-91920","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-91920"},"summary":{"title":"Undertow: undertow: chunkreader message length permits chunk-size overflow","description":"A flaw was found in the ChunkReader component of the Undertow web server, which is used to handle chunked transfer encoding in HTTP requests. The issue occurs because a security check for the chunk size is performed before the value is shifted, allowing a specifically crafted 15-digit chunk size to bypass the limit and overflow into internal state flags. This can cause the server to terminate a request body prematurely and interpret the remaining data as a separate, smuggled request.","state":"PUBLISHED","assigner":"redhat","published_at":"2026-10-30 02:17:10","updated_at":"2026-11-03 18:18:07"},"problem_types":["CWE-444","CWE-444 Inconsistent Interpretation of HTTP Requests"],"metrics":[{"version":"3.1","source":"secalert@redhat.com","type":"Secondary","score":"6.5","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","baseScore":6.5,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"LOW","availabilityImpact":"LOW"}},{"version":"3.1","source":"CNA","type":"CVSS","score":"6.5","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","data":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","version":"3.1"}}],"references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-91920","name":"https://access.redhat.com/security/cve/CVE-2026-91920","refsource":"secalert@redhat.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2528758","name":"https://bugzilla.redhat.com/show_bug.cgi?id=2528758","refsource":"secalert@redhat.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-91920","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-91920","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Red Hat","product":"Red Hat build of Apache Camel for Spring Boot 4","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat Fuse 7","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat JBoss Enterprise Application Platform 7","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat JBoss Enterprise Application Platform 7","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat JBoss Enterprise Application Platform 7","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat JBoss Enterprise Application Platform 7","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat JBoss Enterprise Application Platform 8","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat JBoss Enterprise Application Platform Expansion Pack","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat Single Sign-On 7","version":"","platforms":[]}],"timeline":[{"source":"CNA","time":"2026-09-04T17:07:17.250Z","lang":"en","value":"Reported to Red Hat."},{"source":"CNA","time":"2026-10-29T12:11:57.588Z","lang":"en","value":"Made public."}],"solutions":[],"workarounds":[],"exploits":[],"credits":[{"source":"CNA","value":"Red Hat would like to thank Arpit Jain for reporting this issue.","lang":"en"}],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"91920","cve":"CVE-2026-91920","epss":"0.002350000","percentile":"0.145210000","score_date":"2026-11-02","updated_at":"2026-11-03 00:03:06"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2026-91920","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2026-11-02T20:40:10.909550Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2026-11-02T20:40:18.881Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:camel_spring_boot:4"],"defaultStatus":"affected","packageName":"undertow-servlet","product":"Red Hat build of Apache Camel for Spring Boot 4","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:8"],"defaultStatus":"unknown","packageName":"pki-core:10.6/resteasy","product":"Red Hat Enterprise Linux 8","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:8"],"defaultStatus":"unknown","packageName":"pki-deps:10.6/resteasy","product":"Red Hat Enterprise Linux 8","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:9"],"defaultStatus":"unknown","packageName":"resteasy","product":"Red Hat Enterprise Linux 9","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:jboss_fuse:7"],"defaultStatus":"unaffected","packageName":"undertow-servlet","product":"Red Hat Fuse 7","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/jbossnetwork/restricted/listSoftware.html","cpes":["cpe:/a:redhat:jboss_enterprise_application_platform:7"],"defaultStatus":"affected","packageName":"jboss-eap-7/eap74-els-openjdk11-openshift-rhel8","product":"Red Hat JBoss Enterprise Application Platform 7","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/jbossnetwork/restricted/listSoftware.html","cpes":["cpe:/a:redhat:jboss_enterprise_application_platform:7"],"defaultStatus":"affected","packageName":"jboss-eap-7/eap74-els-openjdk17-openshift-rhel8","product":"Red Hat JBoss Enterprise Application Platform 7","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/jbossnetwork/restricted/listSoftware.html","cpes":["cpe:/a:redhat:jboss_enterprise_application_platform:7"],"defaultStatus":"affected","packageName":"jboss-eap-7/eap74-els-openjdk8-openshift-rhel8","product":"Red Hat JBoss Enterprise Application Platform 7","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/jbossnetwork/restricted/listSoftware.html","cpes":["cpe:/a:redhat:jboss_enterprise_application_platform:7"],"defaultStatus":"affected","packageName":"undertow-servlet","product":"Red Hat JBoss Enterprise Application Platform 7","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/jbossnetwork/restricted/listSoftware.html","cpes":["cpe:/a:redhat:jboss_enterprise_application_platform:8"],"defaultStatus":"affected","packageName":"undertow-servlet","product":"Red Hat JBoss Enterprise Application Platform 8","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/jbossnetwork/restricted/listSoftware.html","cpes":["cpe:/a:redhat:jbosseapxp"],"defaultStatus":"unaffected","packageName":"undertow-servlet","product":"Red Hat JBoss Enterprise Application Platform Expansion Pack","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:red_hat_single_sign_on:7"],"defaultStatus":"affected","packageName":"undertow-servlet","product":"Red Hat Single Sign-On 7","vendor":"Red Hat"}],"credits":[{"lang":"en","value":"Red Hat would like to thank Arpit Jain for reporting this issue."}],"datePublic":"2026-10-29T12:11:57.588Z","descriptions":[{"lang":"en","value":"A flaw was found in the ChunkReader component of the Undertow web server, which is used to handle chunked transfer encoding in HTTP requests. The issue occurs because a security check for the chunk size is performed before the value is shifted, allowing a specifically crafted 15-digit chunk size to bypass the limit and overflow into internal state flags. This can cause the server to terminate a request body prematurely and interpret the remaining data as a separate, smuggled request."}],"metrics":[{"other":{"content":{"namespace":"https://access.redhat.com/security/updates/classification/","value":"Moderate"},"type":"Red Hat severity rating"}},{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","version":"3.1"},"format":"CVSS"}],"problemTypes":[{"descriptions":[{"cweId":"CWE-444","description":"Inconsistent Interpretation of HTTP Requests","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-11-03T17:47:36.306Z","orgId":"53f830b8-0a3f-465b-8143-3b8a9948e749","shortName":"redhat"},"references":[{"tags":["vdb-entry","x_refsource_REDHAT"],"url":"https://access.redhat.com/security/cve/CVE-2026-91920"},{"name":"RHBZ#2528758","tags":["issue-tracking","x_refsource_REDHAT"],"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2528758"}],"timeline":[{"lang":"en","time":"2026-09-04T17:07:17.250Z","value":"Reported to Red Hat."},{"lang":"en","time":"2026-10-29T12:11:57.588Z","value":"Made public."}],"title":"Undertow: undertow: chunkreader message length permits chunk-size overflow","x_generator":{"engine":"cvelib 1.8.0"},"x_redhatCweChain":"CWE-444: Inconsistent Interpretation of HTTP Requests"}},"cveMetadata":{"assignerOrgId":"53f830b8-0a3f-465b-8143-3b8a9948e749","assignerShortName":"redhat","cveId":"CVE-2026-91920","datePublished":"2026-10-30T01:16:53.416Z","dateReserved":"2026-09-15T10:20:33.140Z","dateUpdated":"2026-11-03T17:47:36.306Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-30 02:17:10","lastModifiedDate":"2026-11-03 18:18:07","problem_types":["CWE-444","CWE-444 Inconsistent Interpretation of HTTP Requests"],"metrics":{"cvssMetricV31":[{"source":"secalert@redhat.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","baseScore":6.5,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"LOW","availabilityImpact":"LOW"},"exploitabilityScore":3.9,"impactScore":2.5}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-11-02T20:40:10.909550Z","id":"CVE-2026-91920","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"91920","Ordinal":"1","Title":"Undertow: undertow: chunkreader message length permits chunk-siz","CVE":"CVE-2026-91920","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"91920","Ordinal":"1","NoteData":"A flaw was found in the ChunkReader component of the Undertow web server, which is used to handle chunked transfer encoding in HTTP requests. The issue occurs because a security check for the chunk size is performed before the value is shifted, allowing a specifically crafted 15-digit chunk size to bypass the limit and overflow into internal state flags. This can cause the server to terminate a request body prematurely and interpret the remaining data as a separate, smuggled request.","Type":"Description","Title":"Undertow: undertow: chunkreader message length permits chunk-siz"}]}}}