{"id":"CVE-2026-91920","aliases":["DEBIAN-CVE-2026-91920","EUVD-2026-113473","GHSA-3f65-g3hr-c59r","UBUNTU-CVE-2026-91920"],"status":"published","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.","severity":{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00235,"percentile":0.14559,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-444"],"published":"2026-10-30T01:16:53Z","modified":"2026-11-05T04:38:20Z","affected":[{"source":"osv","ecosystem":"Debian:14","package":"undertow","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.11-1","1.3.16-1","1.3.19-1","1.3.21-1","1.3.23-1","1.3.4-1","1.3.5-1","1.3.7-1","1.4.0-1","1.4.1-1","1.4.18-1","1.4.20-1","1.4.21-1","1.4.21-2","1.4.22-1","1.4.23-1","1.4.23-2","1.4.23-3","1.4.25-1","1.4.25-2","1.4.3-1","1.4.4-1","1.4.6-1","1.4.7-1","1.4.8-1","2.0.23-1","2.0.25-1","2.0.26-1","2.0.27-1","2.0.28-1","2.0.29-1","2.0.30-1","2.1.0-1","2.1.1-1","2.1.3-1","2.2.0-1","2.2.10-1","2.2.12-1","2.2.13-1","2.2.14-1","2.2.16-1","2.2.17-1","2.2.18-1","2.2.19-1","2.2.2-1","2.2.20-1","2.2.21-1","2.2.3-1","2.2.4-1","2.2.5-1","2.2.8-1","2.3.18-1","2.3.18-2","2.3.20-1","2.3.8-1","2.3.8-2"]},{"source":"osv","ecosystem":"Ubuntu:Pro:16.04:LTS","package":"undertow","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.4-1","1.3.5-1","1.3.7-1","1.3.11-1","1.3.16-1","1.3.16-1ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"undertow","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.4.20-1","1.4.21-1","1.4.22-1","1.4.23-1","1.4.23-2build1","1.4.23-3","1.4.23-3ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:20.04:LTS","package":"undertow","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.0.23-1","2.0.27-1","2.0.28-1","2.0.29-1","2.0.29-1ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:22.04:LTS","package":"undertow","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.2.8-1","2.2.12-1","2.2.13-1","2.2.14-1","2.2.16-1","2.2.16-1ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:24.04:LTS","package":"undertow","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.3.8-2","2.3.8-2ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"undertow","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.3.20-1ubuntu1"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"undertow","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.3.18-2","2.3.20-1","2.3.20-1ubuntu1"]}],"products":[{"vendor":"red hat","product":"red hat build of apache camel for spring boot 4"},{"vendor":"red hat","product":"red hat enterprise linux 8"},{"vendor":"red hat","product":"red hat enterprise linux 9"},{"vendor":"red hat","product":"red hat fuse 7"},{"vendor":"red hat","product":"red hat jboss enterprise application platform 7"},{"vendor":"red hat","product":"red hat jboss enterprise application platform 8"},{"vendor":"red hat","product":"red hat jboss enterprise application platform expansion pack"},{"vendor":"red hat","product":"red hat single sign-on 7"}],"references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-91920","tags":["vdb-entry","x_refsource_REDHAT","report"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2528758","tags":["issue-tracking","x_refsource_REDHAT","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-91920"},{"url":"https://github.com/advisories/GHSA-3f65-g3hr-c59r"},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-91920","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-91920","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-91920","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-91920","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.","status":"published","published":"2026-10-30T01:16:53.416Z","modified":"2026-11-06T01:46:34.006Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","level":"medium","assessor":"cna"}],"cwes":["CWE-444"],"updated_at":"2026-11-06T02:55:55.947181Z"}],"euvd":[{"id":"EUVD-2026-113473","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.","status":"published","published":"2026-10-30T01:16:53Z","modified":"2026-11-06T01:46:34Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","level":"medium"}],"updated_at":"2026-11-06T03:02:58.554056Z"}],"ghsa":[{"id":"GHSA-3f65-g3hr-c59r","title":"A flaw was found in the ChunkReader component of the Undertow web server, which is used to handle...","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.","status":"published","published":"2026-10-30T03:32:02Z","modified":"2026-10-30T03:32:07Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","level":"medium"}],"cwes":["CWE-444"],"updated_at":"2026-11-02T15:14:41.240878Z"}],"nvd":[{"id":"CVE-2026-91920","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.","status":"published","published":"2026-10-30T02:17:10.14Z","modified":"2026-11-06T02:17:57.957Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","level":"medium","assessor":"secondary"}],"cwes":["CWE-444"],"updated_at":"2026-11-06T06:59:07.310069Z"}],"osv":[{"id":"DEBIAN-CVE-2026-91920","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.","status":"published","published":"2026-10-30T02:17:10.14Z","modified":"2026-11-04T09:47:34.293935734Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","level":"medium"}],"updated_at":"2026-11-04T10:05:32.187009Z"},{"id":"UBUNTU-CVE-2026-91920","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.","status":"published","published":"2026-10-30T02:17:00Z","modified":"2026-11-05T04:38:20Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","level":"medium"}],"updated_at":"2026-11-05T13:33:42.748455Z"}]}}