{"cve":"CVE-2021-23937","nvd":{"published":"2021-05-25T17:15:08.187","modified":"2026-06-17T03:39:03.293","status":"Modified","description":"A DNS proxy and possible amplification attack vulnerability in WebClientInfo of Apache Wicket allows an attacker to trigger arbitrary DNS lookups from the server when the X-Forwarded-For header is not properly sanitized. This DNS lookup can be engineered to overload an internal DNS server or to slow down request processing of the Apache Wicket application causing a possible denial of service on either the internal infrastructure or the web application itself. This issue affects Apache Wicket Apache Wicket 9.x version 9.2.0 and prior versions; Apache Wicket 8.x version 8.11.0 and prior versions; Apache Wicket 7.x version 7.17.0 and prior versions and Apache Wicket 6.x version 6.2.0 and later versions.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-200"],"references":["https://lists.apache.org/thread.html/r127c0c1f3cb71e5bc619ad1e4b898b97c49758d1f20a54042966473e%40%3Cannounce.wicket.apache.org%3E","https://lists.apache.org/thread.html/r127c0c1f3cb71e5bc619ad1e4b898b97c49758d1f20a54042966473e%40%3Cusers.wicket.apache.org%3E","https://lists.apache.org/thread.html/r8ccbd91b56ebf045d151bd4282bfeea7842a0698a0b76118fca8fe78%40%3Cdev.wicket.apache.org%3E","https://lists.apache.org/thread.html/rc2ef22f90793e158cef65a7e370cdbca023c499d1403d65feeca870d%40%3Cusers.wicket.apache.org%3E","https://lists.apache.org/thread.html/r127c0c1f3cb71e5bc619ad1e4b898b97c49758d1f20a54042966473e%40%3Cannounce.wicket.apache.org%3E"],"products":["apache:wicket"],"source":"nvd","synced_at":"2026-10-19T21:18:09.669877188+00:00"},"epss":{"cve":"CVE-2021-23937","score":0.0426,"percentile":0.91068,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-hmhg-95wh-r699","url":"https://osv.dev/vulnerability/GHSA-hmhg-95wh-r699","summary":"DNS based denial of service in Apache Wicket","modified":"2024-02-16T08:11:59.161510Z","packages":[{"ecosystem":"Maven","name":"org.apache.wicket:wicket-core","purl":"pkg:maven/org.apache.wicket/wicket-core","ranges":[">=9.0.0 <9.3.0"],"fixed":["9.3.0"]},{"ecosystem":"Maven","name":"org.apache.wicket:wicket-core","purl":"pkg:maven/org.apache.wicket/wicket-core","ranges":[">=8.0.0 <8.12.0"],"fixed":["8.12.0"]},{"ecosystem":"Maven","name":"org.apache.wicket:wicket-core","purl":"pkg:maven/org.apache.wicket/wicket-core","ranges":["<7.18.0"],"fixed":["7.18.0"]}]}],"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."]}