CVE-2011-2536: n/a vulnerability

CVE-2011-2536: chan_sip.c in the SIP channel driver in Asterisk Open Source 1.4.x before 1.4.41.2, 1.6.2.x before 1.6.2.18...

chan_sip.c in the SIP channel driver in Asterisk Open Source 1.4.x before 1.4.41.2, 1.6.2.x before 1.6.2.18.2, and 1.8.x before 1.8.4.4, and Asterisk Business Edition C.3.x before C.3.7.3, disregards the alwaysauthreject option and generates different responses for invalid SIP requests depending on whether the user account exists, which allows remote attackers to enumerate account names via a series of requests.

UnknownCVSS not scoredNot KEV-listedUpdatedAug 6, 2024, 23:08 UTC (UTC+00:00)

Security readout for executives and security teams

This issue lets a remote party learn whether SIP account names exist on affected Asterisk systems. It does not describe call takeover or code execution, but account enumeration can support later password guessing, fraud attempts, or targeted intrusion against voice infrastructure. Exposure is most likely where affected Asterisk SIP services are reachable by untrusted networks or the internet. Internal-only PBX deployments still matter if attackers can reach SIP from compromised networks or partner connections. Treat as a targeted hardening and upgrade item for voice infrastructure. It is not evidenced as actively exploited here, but exposed PBX systems can turn account discovery into higher-risk credential and fraud activity. Mitigation focus: Upgrade Asterisk Open Source to 1.4.41.2, 1.6.2.18.2, 1.8.4.4, or later.; Upgrade Asterisk Business Edition C.3.x to C.3.7.3 or later.; Review the Asterisk AST-2011-011 advisory before applying production changes..

Prepared: Jun 27, 2026, 18:09 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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Vulnerability profileCVE Program record

Severity: Unknown
CVSS: Not scored
Known Exploited: No
Published: Jul 6, 2011, 19:00 UTC (UTC+00:00)

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

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1Source links

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Source materials

CVE List V5 sourceCVE List V5

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus

n/an/an/aListed

Weakness

CWE details

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