Security readout for executives and security teams
Plain-English summary
This flaw can let a remote, unauthenticated attacker crash and reload an affected Cisco IOS XE device when it is doing NAT processing for SIP traffic. The business impact is service interruption for networks or voice-related traffic paths relying on that device.
Executive priority
Treat as high priority for networks where IOS XE devices sit on voice or edge NAT paths. The main risk is outage, not data theft, but device reloads can disrupt business operations and communications.
Technical view
CVE-2019-12646 affects the NAT SIP ALG in Cisco IOS XE Software. Improper processing of transient SIP packets during NAT can trigger device reload. The CVSS 3.0 score is 8.6, with network attack vector, low complexity, no privileges, no user interaction, and high availability impact.
Likely exposure
Exposure is most likely where Cisco IOS XE devices perform NAT for SIP packets and allow UDP port 5060 traffic to pass through them. The provided sources do not identify specific affected releases in the bundle.
Exploitation context
The source bundle describes remote unauthenticated exploitation for denial of service. It does not show CISA KEV listing or other cited evidence of active exploitation, so active exploitation should not be assumed.
Researcher notes
Key conditions are IOS XE, NAT for SIP packets, and crafted SIP traffic through the device. The bundle does not include affected release ranges, exploit maturity, or fixed-version details; use Cisco’s advisory for authoritative product validation.
Mitigation direction
- Check Cisco’s advisory for affected releases and fixed software guidance.
- Prioritize upgrades or configuration changes for exposed SIP NAT paths.
- Restrict UDP 5060 transit to required sources where operationally feasible.
- Review whether SIP ALG/NAT processing is required on edge devices.
Validation and detection
- Inventory Cisco IOS XE devices handling NAT for SIP traffic.
- Identify paths where UDP 5060 traverses IOS XE NAT devices.
- Compare device software releases against Cisco’s advisory.
- Review device reload logs for SIP-related timing patterns.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-399: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2019-12646 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.6 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H3.94Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
8.6HighVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20190925 Cisco IOS XE Software NAT Session Initiation Protocol Application Layer Gateway Denial of Service VulnerabilityCVE reference · vendor-advisory, x_refsource_CISCO
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Resource Management Errors
Resource Management Errors represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.