CVE-2008-3903

Asterisk Open Source 1.2.x before 1.2.32, 1.4.x before 1.4.24.1, and 1.6.0.x before 1.6.0.8; Asterisk Business Edition A.x.x, B.x.x before B.2.5.8, C.1.x.x before C.1.10.5, and C.2.x.x before C.2.3.3; s800i 1.3.x before 1.3.0.2; and Trixbox PBX 2.6.1, when Digest authentication and authalwaysreject are enabled, generates different responses depending on whether a SIP username is valid, which allows remote attackers to enumerate valid usernames.

Published: 2008-09-04 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2008-3903 is rated Moderate Risk (41.8/100): CVSS Low severity, with medium exploitation likelihood (EPSS 1.85%). EPSS rose +1.12% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

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-2008-3903

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 2026-06-15 0.73% 1.85% +1.12%
2 2026-03-19 0.84% 0.73% -0.11%
3 2026-01-29 — 0.84% —

Full EPSS history (13 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2008-3903

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.5 2.0 LOW
AV:N/AC:M/Au:S/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 6.8 2.9 [email protected]

Weakness enumeration for CVE-2008-3903

OS Trackers for CVE-2008-3903

vendor priority summary link
debian low CVE-2008-3903 low priority: Debian including 1 source packages (asterisk), 2 status rows across 2 suites (bullseye, sid): resolved 2. https://security-tracker.debian.org/tracker/CVE-2008-3903
gentoo normal CVE-2008-3903: 1 GLSA(s) (200905-01), 1 atom(s) (net-misc/asterisk); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2008-3903
redhat — — https://access.redhat.com/security/cve/CVE-2008-3903
ubuntu low CVE-2008-3903 low priority: Ubuntu including 1 source packages (asterisk), 10 status rows across 10 suites (dapper, feisty, gutsy, hardy, intrepid, jaunty, karmic, lucid, maverick, upstream): ignored 5, not-affected 3, needs-triage 1, released 1. https://ubuntu.com/security/CVE-2008-3903

NVD evaluator notes for CVE-2008-3903

Comment: Additional details can be found here: http://www.voipsa.org/pipermail/voipsec_voipsa.org/2006-May/001628.html

Affected software / configurations for CVE-2008-3903

Vendor Product Version Raw CPE
asterisk p_b_x 1.2 cpe:2.3:a:asterisk:p_b_x:1.2:*:*:*:*:*:*:*
asterisk p_b_x 1.2.22 cpe:2.3:a:asterisk:p_b_x:1.2.22:*:*:*:*:*:*:*
asterisk p_b_x 1.4.21.1 cpe:2.3:a:asterisk:p_b_x:1.4.21.1:*:*:*:*:*:*:*
asterisk p_b_x 1.6 cpe:2.3:a:asterisk:p_b_x:1.6:*:*:*:*:*:*:*
trixbox pbx 2.6.1 cpe:2.3:a:trixbox:pbx:2.6.1:*:*:*:*:*:*:*

References for CVE-2008-3903

cvelogic Threat Intelligence