Is CVE-2011-2666 in the CISA KEV catalog?

No. CVE-2011-2666 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2011-2666?

CVE-2011-2666 has a CVSS v2 base score of 5.0 (MEDIUM).

What is the EPSS score for CVE-2011-2666?

CVE-2011-2666 has an EPSS score of 1.33% (68th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2011-2666?

Upgrade asterisk on debian 11 to 1:1.8.3.3-1 or later.

CVE & CISA-KEV Catalog

CVE-2011-2666

MEDIUM

5.0

CVSS v2

NVD

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.

CWE-16

How to fix

Remediation Available

asteriskDebian

Fixed in:1:1.8.3.3-1CVE-2011-2666

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v2 Vector

No CVSS vector data available.

Exploit Intelligence

1.33%probability of exploitation in 30 days

68thpercentile

Moderate risk: more likely to be exploited than 68% of all known CVEs.

References

Vendor Advisory1

downloads.asterisk.org

Other references1

exchange.xforce.ibmcloud.com

Related Vulnerabilities

Other CWE-16 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2009-2335	Medium	5.0	85%	-	Fix
CVE-2004-2687	High	9.3	81%	-	Fix
CVE-2006-3677	High	7.5	78%	-	Fix
CVE-2011-4404	Medium	5.0	60%	-	-
CVE-2006-0848	Medium	5.1	58%	-	-
CVE-2007-3898	Medium	6.4	55%	-	-

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-29.