CVE-2009-4409

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.

Published: 2009-12-23 Last update: 2026-04-23 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2009-4409 is rated Low Risk (27.7/100): CVSS Low severity, with medium exploitation likelihood (EPSS 0.29%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2009-4409

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-03-17 0.55% 0.29% -0.26%
2 2024-09-17 0.47% 0.55% +0.09%
3 2024-03-15 — 0.47% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2009-4409

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
2.6 2.0 LOW
AV:N/AC:H/Au:N/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:H)
Exploitation requires uncommon or highly specific conditions.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 4.9 2.9 [email protected]

Weakness enumeration for CVE-2009-4409

Affected software / configurations for CVE-2009-4409

Vendor Product Version Raw CPE
iij seil\/b1 1.00 cpe:2.3:h:iij:seil\/b1:1.00:*:*:*:*:*:*:*
iij seil\/b1 2.01 cpe:2.3:h:iij:seil\/b1:2.01:*:*:*:*:*:*:*
iij seil\/b1 2.10 cpe:2.3:h:iij:seil\/b1:2.10:*:*:*:*:*:*:*
iij seil\/b1 2.20 cpe:2.3:h:iij:seil\/b1:2.20:*:*:*:*:*:*:*
iij seil\/b1 2.30 cpe:2.3:h:iij:seil\/b1:2.30:*:*:*:*:*:*:*
iij seil\/b1 2.40 cpe:2.3:h:iij:seil\/b1:2.40:*:*:*:*:*:*:*
iij seil\/b1 2.41 cpe:2.3:h:iij:seil\/b1:2.41:*:*:*:*:*:*:*
iij seil\/b1 2.42 cpe:2.3:h:iij:seil\/b1:2.42:*:*:*:*:*:*:*
iij seil\/b1 2.50 cpe:2.3:h:iij:seil\/b1:2.50:*:*:*:*:*:*:*
iij seil\/b1 2.51 cpe:2.3:h:iij:seil\/b1:2.51:*:*:*:*:*:*:*
iij seil\/b1 2.52 cpe:2.3:h:iij:seil\/b1:2.52:*:*:*:*:*:*:*

References for CVE-2009-4409

cvelogic Threat Intelligence