{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-91920","assignerOrgId":"53f830b8-0a3f-465b-8143-3b8a9948e749","state":"PUBLISHED","assignerShortName":"redhat","dateReserved":"2026-09-15T10:20:33.140Z","datePublished":"2026-10-30T01:16:53.416Z","dateUpdated":"2026-10-30T01:16:53.416Z"},"containers":{"cna":{"title":"Undertow: undertow: chunkreader message length permits chunk-size overflow","metrics":[{"other":{"content":{"value":"Moderate","namespace":"https://access.redhat.com/security/updates/classification/"},"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"}],"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."}],"affected":[{"vendor":"Red Hat","product":"Red Hat build of Apache Camel for Spring Boot 4","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"undertow-servlet","defaultStatus":"affected","cpes":["cpe:/a:redhat:camel_spring_boot:4"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"pki-core:10.6/resteasy","defaultStatus":"unknown","cpes":["cpe:/o:redhat:enterprise_linux:8"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"pki-deps:10.6/resteasy","defaultStatus":"unknown","cpes":["cpe:/o:redhat:enterprise_linux:8"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"resteasy","defaultStatus":"unknown","cpes":["cpe:/o:redhat:enterprise_linux:9"]},{"vendor":"Red Hat","product":"Red Hat Fuse 7","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"undertow-servlet","defaultStatus":"affected","cpes":["cpe:/a:redhat:jboss_fuse:7"]},{"vendor":"Red Hat","product":"Red Hat JBoss Enterprise Application Platform 7","collectionURL":"https://access.redhat.com/jbossnetwork/restricted/listSoftware.html","packageName":"jboss-eap-7/eap74-els-openjdk11-openshift-rhel8","defaultStatus":"affected","cpes":["cpe:/a:redhat:jboss_enterprise_application_platform:7"]},{"vendor":"Red Hat","product":"Red Hat JBoss Enterprise Application Platform 7","collectionURL":"https://access.redhat.com/jbossnetwork/restricted/listSoftware.html","packageName":"jboss-eap-7/eap74-els-openjdk17-openshift-rhel8","defaultStatus":"affected","cpes":["cpe:/a:redhat:jboss_enterprise_application_platform:7"]},{"vendor":"Red Hat","product":"Red Hat JBoss Enterprise Application Platform 7","collectionURL":"https://access.redhat.com/jbossnetwork/restricted/listSoftware.html","packageName":"jboss-eap-7/eap74-els-openjdk8-openshift-rhel8","defaultStatus":"affected","cpes":["cpe:/a:redhat:jboss_enterprise_application_platform:7"]},{"vendor":"Red Hat","product":"Red Hat JBoss Enterprise Application Platform 7","collectionURL":"https://access.redhat.com/jbossnetwork/restricted/listSoftware.html","packageName":"undertow-servlet","defaultStatus":"affected","cpes":["cpe:/a:redhat:jboss_enterprise_application_platform:7"]},{"vendor":"Red Hat","product":"Red Hat JBoss Enterprise Application Platform 8","collectionURL":"https://access.redhat.com/jbossnetwork/restricted/listSoftware.html","packageName":"undertow-servlet","defaultStatus":"affected","cpes":["cpe:/a:redhat:jboss_enterprise_application_platform:8"]},{"vendor":"Red Hat","product":"Red Hat JBoss Enterprise Application Platform Expansion Pack","collectionURL":"https://access.redhat.com/jbossnetwork/restricted/listSoftware.html","packageName":"undertow-servlet","defaultStatus":"unaffected","cpes":["cpe:/a:redhat:jbosseapxp"]},{"vendor":"Red Hat","product":"Red Hat Single Sign-On 7","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"undertow-servlet","defaultStatus":"affected","cpes":["cpe:/a:redhat:red_hat_single_sign_on:7"]}],"references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-91920","tags":["vdb-entry","x_refsource_REDHAT"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2528758","name":"RHBZ#2528758","tags":["issue-tracking","x_refsource_REDHAT"]}],"datePublic":"2026-10-29T12:11:57.588Z","problemTypes":[{"descriptions":[{"cweId":"CWE-444","description":"Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')","lang":"en","type":"CWE"}]}],"x_redhatCweChain":"CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')","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."}],"credits":[{"lang":"en","value":"Red Hat would like to thank Arpit Jain for reporting this issue."}],"providerMetadata":{"orgId":"53f830b8-0a3f-465b-8143-3b8a9948e749","shortName":"redhat","dateUpdated":"2026-10-30T01:16:53.416Z"},"x_generator":{"engine":"cvelib 1.8.0"}}}}