CVE-2019-12646

CVE-2019-12646 is a high-severity vulnerability in Cisco Ios Xe with a CVSS 3.x base score of 7.5. 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-665.

Key facts

• Severity: High (CVSS 3.x base score 7.5)
• CVSS v2: 7.8
• EPSS exploit prediction: 2% (78th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-665
• Affected product: Cisco Ios Xe
• Published: 2019-09-25
• Last modified: 2026-06-17

Description

A vulnerability in the Network Address Translation (NAT) Session Initiation Protocol (SIP) Application Layer Gateway (ALG) of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to improper processing of transient SIP packets on which NAT is performed on an affected device. An attacker could exploit this vulnerability by using UDP port 5060 to send crafted SIP packets through an affected device that is performing NAT for SIP packets. A successful exploit could allow an attacker to cause the device to reload, resulting in a denial of service (DoS) condition.

Frequently asked questions

What is CVE-2019-12646?

A vulnerability in the Network Address Translation (NAT) Session Initiation Protocol (SIP) Application Layer Gateway (ALG) of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to improper processing of transient SIP packets on which NAT is performed on an affected device. An attacker could exploit this vulnerability by using UDP port 5060 to send crafted SIP packets through an affected device that is performing NAT for SIP packets. A successful exploit could allow an attacker to cause the device to reload, resulting in a denial of service (DoS) condition.

How severe is CVE-2019-12646?

CVE-2019-12646 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2019-12646 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-12646?

CVE-2019-12646 primarily affects Cisco Ios Xe. In total, 13 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-12646?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2019-12646 published?

CVE-2019-12646 was published on 2019-09-25 and last updated on 2026-06-17.

References

• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190925-sip-alg

Affected products (13)

• cpe:2.3:o:cisco:ios_xe:15.4\(3\)s:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios_xe:15.5\(3\)s:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios_xe:15.6\(1\)s:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios_xe:16.3.1:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios_xe:16.4.1:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios_xe:16.5.1:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios_xe:16.6.1:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios_xe:16.7.1:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios_xe:16.8.1:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios_xe:16.9.1:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios_xe:16.10.1:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios_xe:16.11.1:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios_xe:16.12.1:*:*:*:*:*:*:*

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