Security readout for executives and security teams
Plain-English summary
This Cisco Unified Communications Manager flaw can let an unauthenticated remote attacker disrupt phone service by sending malformed SIP traffic. Successful exploitation can force connected phones to start new registration, causing temporary voice service interruption. The business concern is availability, not data theft.
Executive priority
Prioritize remediation for CUCM systems supporting critical calling, contact centers, emergency workflows, or exposed SIP paths. The issue can disrupt service without authentication, so availability impact can be material even though confidentiality and integrity are not implicated.
Technical view
CVE-2019-1887 is a SIP input-validation denial-of-service issue in Cisco Unified Communications Manager. The CVSS 3.0 score is 8.6 with network attack vector, low complexity, no privileges, no user interaction, scope changed, and high availability impact. Affected versions are not specified in the provided bundle.
Likely exposure
Exposure is likely where Cisco Unified Communications Manager receives SIP traffic from untrusted or poorly segmented networks. The bundle does not specify affected versions, configurations, or internet-exposure requirements, so asset inventory and Cisco advisory review are necessary.
Exploitation context
The provided sources describe unauthenticated remote DoS via malformed SIP traffic. CISA KEV status is false in the bundle, and no cited source here confirms active exploitation. Treat exploitation status as unconfirmed, not actively exploited.
Researcher notes
The source bundle names Cisco Unified Communications Manager but lists versions as unspecified. CVE metadata maps the issue to CWE-787, though the description emphasizes insufficient SIP input validation. Validate against Cisco’s advisory before concluding product version impact or remediation status.
Mitigation direction
- Identify Cisco Unified Communications Manager deployments and ownership.
- Review Cisco’s advisory for affected releases and official remediation.
- Apply Cisco-provided fixed software or workaround where applicable.
- Limit SIP reachability to necessary trusted voice paths where operationally feasible.
- Monitor for unusual SIP errors or mass phone re-registration events.
Validation and detection
- Confirm whether Cisco Unified Communications Manager is deployed.
- Compare installed versions and configurations against Cisco’s advisory.
- Review voice logs for unexpected phone re-registration bursts.
- Check network paths that can send SIP traffic to CUCM.
- Avoid production testing with malformed SIP packets.
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-787: 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-2019-1887 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
- 20190703 Cisco Unified Communications Manager Session Initiation Protocol 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.
Out-of-bounds Write
Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.