CVE-2011-2666

The default configuration of the SIP channel driver in Asterisk Open Source 1.4.x through 1.4.41.2 and 1.6.2.x through 1.6.2.18.2 does not enable the alwaysauthreject option, which allows remote attackers to enumerate account names by making a series of invalid SIP requests and observing the differences in the responses for different usernames, a different vulnerability than CVE-2011-2536.

CVSS 5.0 · Medium

External lookup

Potential internet exposure

Potential exposure only — not proof of vulnerability.Shodan results indicate potentially internet-exposed products, not confirmed vulnerable systems. They do not confirm that any returned system is vulnerable to CVE-2011-2666.

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Product CPE queries

Derived from this CVE's existing NVD CPE 2.3 records; the application, operating-system, or hardware part is retained.

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Exact CVE query

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Metadata

Canonical fields

NVD status

Unavailable

Published

Jul 6, 2011

Modified

Jun 16, 2026

Official record

Authoritative NVD record

CVSS vector

AV:N/AC:L/Au:N/C:P/I:N/A:N

CWE IDs

Vendor classifications

How this vector reads

CVSS 2.0 base metrics decoded below. This explanation does not recalculate or change the NVD score.

Access Vector (AV): Network. The vulnerable system can be reached across network boundaries.
Access Complexity (AC): Low. No special conditions beyond the attacker-controlled steps are required.
Authentication (Au): None. The attacker does not need to authenticate.
Confidentiality Impact (C): Partial. There is a limited impact to this security property.
Integrity Impact (I): None. There is no impact to this security property.
Availability Impact (A): None. There is no impact to this security property.

Signals

Exploitation indicators

0 stored signals · no KEV · 0 OTX pulses