{"cve":"CVE-2009-4409","nvd":{"published":"2009-12-23T21:30:00.313","modified":"2026-06-16T23:13:36.723","status":"Modified","description":"The (1) CHAP and (2) MS-CHAP-V2 authentication capabilities in the PPP Access Concentrator (PPPAC) function in Internet Initiative Japan SEIL/B1 firmware 1.00 through 2.52 use the same challenge for each authentication attempt, which allows remote attackers to bypass authentication via a replay attack.","cvss_v4":null,"cvss_v3":null,"cwes":["CWE-287"],"references":["http://jvn.jp/en/jp/JVN49602378/index.html","http://jvndb.jvn.jp/ja/contents/2009/JVNDB-2009-000079.html","http://secunia.com/advisories/37628","http://www.osvdb.org/61118","http://www.securityfocus.com/bid/37293"],"products":["iij:seil\\/b1"],"source":"nvd","synced_at":"2026-10-19T19:55:32.599380760+00:00"},"epss":{"cve":"CVE-2009-4409","score":0.01356,"percentile":0.71644,"date":"2026-10-31"},"kev":null,"osv":[],"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."]}