{"cve":"CVE-2025-12543","nvd":{"published":"2026-01-07T17:15:55.093","modified":"2026-10-14T17:17:40.837","status":"Modified","description":"A flaw was found in the Undertow HTTP server core, which is used in WildFly, JBoss EAP, and other Java applications. The Undertow library fails to properly validate the Host header in incoming HTTP requests.As a result, requests containing malformed or malicious Host headers are processed without rejection, enabling attackers to poison caches, perform internal network scans, or hijack user sessions.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H","score":9.6},"cwes":["CWE-20"],"references":["https://access.redhat.com/errata/RHSA-2026:0383","https://access.redhat.com/errata/RHSA-2026:0384","https://access.redhat.com/errata/RHSA-2026:0386","https://access.redhat.com/errata/RHSA-2026:33371","https://access.redhat.com/errata/RHSA-2026:33372"],"products":["redhat:build_of_apache_camel","redhat:data_grid","redhat:fuse","redhat:jboss_enterprise_application_platform","redhat:jboss_enterprise_application_platform_expansion_pack","redhat:process_automation","redhat:single_sign-on","redhat:undertow"],"source":"nvd","synced_at":"2026-10-19T22:19:41.481987139+00:00"},"epss":{"cve":"CVE-2025-12543","score":0.01333,"percentile":0.70916,"date":"2026-10-26"},"kev":null,"osv":[{"id":"GHSA-j382-5jj3-vw4j","url":"https://osv.dev/vulnerability/GHSA-j382-5jj3-vw4j","summary":"Undertow HTTP server core doesn't properly validate the Host header in incoming HTTP requests","modified":"2026-09-10T03:50:33.364740627Z","packages":[{"ecosystem":"Maven","name":"io.undertow:undertow-core","purl":"pkg:maven/io.undertow/undertow-core","ranges":["2.4.0.Alpha1"],"fixed":[]},{"ecosystem":"Maven","name":"io.undertow:undertow-core","purl":"pkg:maven/io.undertow/undertow-core","ranges":[">=2.3.0.Alpha1 <2.3.21.Final"],"fixed":["2.3.21.Final"]},{"ecosystem":"Maven","name":"io.undertow:undertow-core","purl":"pkg:maven/io.undertow/undertow-core","ranges":["<2.2.39.Final"],"fixed":["2.2.39.Final"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}