CVE-2011-4597

CVE-2011-4597 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-200.

Key facts

• Severity: Medium (CVSS 2.0 base score 5.0)
• EPSS exploit prediction: 3% (87th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-200
• Affected product: Digium Asterisk
• Published: 2011-12-15
• Last modified: 2026-06-16

Description

The SIP over UDP implementation in Asterisk Open Source 1.4.x before 1.4.43, 1.6.x before 1.6.2.21, and 1.8.x before 1.8.7.2 uses different port numbers for responses to invalid requests depending on whether a SIP username exists, which allows remote attackers to enumerate usernames via a series of requests.

Frequently asked questions

What is CVE-2011-4597?

The SIP over UDP implementation in Asterisk Open Source 1.4.x before 1.4.43, 1.6.x before 1.6.2.21, and 1.8.x before 1.8.7.2 uses different port numbers for responses to invalid requests depending on whether a SIP username exists, which allows remote attackers to enumerate usernames via a series of requests.

How severe is CVE-2011-4597?

CVE-2011-4597 has a CVSS 2.0 base score of 5.0, rated medium severity.

Is CVE-2011-4597 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2011-4597?

CVE-2011-4597 primarily affects Digium Asterisk. In total, 208 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2011-4597?

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

When was CVE-2011-4597 published?

CVE-2011-4597 was published on 2011-12-15 and last updated on 2026-06-16.

References

• http://archives.neohapsis.com/archives/bugtraq/2011-12/0151.html
• http://downloads.asterisk.org/pub/security/AST-2011-013.html
• http://lists.digium.com/pipermail/asterisk-dev/2011-November/052191.html
• http://openwall.com/lists/oss-security/2011/12/09/3
• http://openwall.com/lists/oss-security/2011/12/09/4
• http://osvdb.org/77597
• http://secunia.com/advisories/47273
• http://www.debian.org/security/2011/dsa-2367

Affected products (208)

• cpe:2.3:a:digium:asterisk:1.8.0:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.0:beta1:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.0:beta2:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.0:beta3:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.0:beta4:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.0:beta5:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.0:rc2:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.0:rc3:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.0:rc4:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.0:rc5:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.1:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.1:rc1:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.1.1:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.1.2:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.2:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.2.1:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.2.2:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.2.3:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.2.4:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.3:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.3:rc1:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.3:rc2:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.3:rc3:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.3.1:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.3.2:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.3.3:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.4:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.4:rc1:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.4:rc2:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.4:rc3:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.4.1:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.4.2:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.4.3:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.4.4:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.5:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.5:rc1:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.5.0:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.6.0:*:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.6.0:rc1:*:*:*:*:*:*
• cpe:2.3:a:digium:asterisk:1.8.6.0:rc2:*:*:*:*:*:*

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