Security readout for executives and security teams
Plain-English summary
This flaw can let traffic slip past Cisco Firepower filtering when streams are reassembled incorrectly. A remote unauthenticated attacker could use crafted network streams to deliver requests to protected systems that policy would normally block. It is not described as device takeover, but it can weaken a key security control in front of business systems.
Executive priority
Treat this as a control-bypass risk, not a full device compromise. Prioritize environments where Firepower inspection protects sensitive applications or internet-facing services, then follow Cisco guidance for version validation and remediation.
Technical view
CVE-2019-1978 is an improper traffic-stream reassembly issue in Cisco Firepower Threat Defense, FirePOWER Services Software for ASA, and Firepower Management Center Software. CVSS 3.0 is 5.8: network reachable, low complexity, no privileges, no user interaction, changed scope, and low integrity impact.
Likely exposure
Exposure is most relevant where affected Cisco Firepower products inspect traffic for protected networks. The source bundle does not identify specific vulnerable versions, so teams must verify deployed releases against Cisco’s advisory.
Exploitation context
The sources describe unauthenticated remote exploitation by crafted streams that bypass filtering. The bundle does not cite CISA KEV listing or other evidence of active exploitation.
Researcher notes
Evidence is limited to the CVE record and Cisco advisory metadata in the bundle. The vulnerability class is stream reassembly bypass, CWE-264, with integrity-only impact in CVSS. No public exploit status or precise version range is provided here.
Mitigation direction
- Check Cisco’s advisory for affected and fixed software releases.
- Prioritize remediation on internet-facing or high-trust network inspection paths.
- Apply Cisco-recommended updates or mitigations where applicable.
- Use downstream controls to reduce reliance on one filtering layer.
Validation and detection
- Inventory Cisco Firepower Threat Defense, FirePOWER Services for ASA, and FMC deployments.
- Compare installed versions against Cisco’s advisory.
- Identify protected systems relying on affected filtering paths.
- Review security logs for unexpected policy bypass symptoms.
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-264: 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-2019-1978 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
- Medium
- CVSS
- 5.8 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
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:L/A:N3.91.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
5.8MediumVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- 20190816 Cisco Firepower Threat Defense Software Stream Reassembly Bypass 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.
Permissions, Privileges, and Access Controls
Permissions, Privileges, and Access Controls represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.