How severe is CVE-2011-2666?

CVE-2011-2666 has a CVSS 2.0 base score of 5.0, rated medium severity.

Is CVE-2011-2666 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2011-2666?

CVE-2011-2666 primarily affects Digium Asterisk. In total, 158 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2011-2666?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2011-2666 published?

CVE-2011-2666 was published on 2011-07-06 and last updated on 2026-06-16.

CVE-2011-2666

CVE-2011-2666 is a medium-severity vulnerability in Digium Asterisk with a CVSS 2.0 base score of 5.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-16.

Key facts

Severity: Medium (CVSS 2.0 base score 5.0)
EPSS exploit prediction: 1% (68th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-16
Affected product: Digium Asterisk
Published: 2011-07-06
Last modified: 2026-06-16

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2011-2666?: CVE-2011-2666 has a CVSS 2.0 base score of 5.0, rated medium severity.
Is CVE-2011-2666 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-2666?: CVE-2011-2666 primarily affects Digium Asterisk. In total, 158 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2011-2666?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2011-2666 published?: CVE-2011-2666 was published on 2011-07-06 and last updated on 2026-06-16.

References

Affected products (158)

cpe:2.3:a:digium:asterisk:1.6.2.0:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.0:rc2:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.0:rc3:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.0:rc4:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.0:rc5:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.0:rc6:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.0:rc7:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.0:rc8:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.1:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.1:rc1:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.2:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.3:rc2:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.4:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.5:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.6:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.6:rc1:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.6:rc2:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.15:rc1:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.16:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.16:rc1:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.16.1:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.16.2:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.17:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.17:rc1:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.17:rc2:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.17:rc3:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.17.1:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.17.2:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.17.3:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.18:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.18:rc1:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.18.1:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.6.2.18.2:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.4.0:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.4.0:beta1:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.4.0:beta2:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.4.0:beta3:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.4.0:beta4:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.4.1:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:1.4.2:*:*:*:*:*:*:*

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