Security readout for executives and security teams
Plain-English summary
This Cisco ASA/FTD flaw can crash and reload affected firewall/VPN devices, causing service disruption. It does not expose encrypted data. The issue is limited to Cisco ASA 9.16.1 and Cisco FTD 7.0.0, but those systems can be important network choke points, so downtime risk is meaningful.
Executive priority
Treat this as a high-priority availability risk for affected Cisco VPN/firewall infrastructure. It is not a data-theft issue, but a crash and reload on perimeter security devices can interrupt remote access, site-to-site connectivity, and dependent business services.
Technical view
CVE-2021-1422 is a high-severity IPsec denial-of-service issue in Cisco ASA and FTD software cryptography handling. A logic error in decryption error handling can trigger an unexpected device reload when malicious packets traverse an established IPsec connection. CVSS is 7.7, with high availability impact and no confidentiality or integrity impact.
Likely exposure
Exposure appears narrow: only Cisco ASA Software Release 9.16.1 and Cisco FTD Software Release 7.0.0 are identified. Risk is highest where those devices terminate IPsec VPN connections or operate in environments where a man-in-the-middle position is plausible.
Exploitation context
The source describes exploitation by an authenticated remote attacker or an unauthenticated attacker in a man-in-the-middle position. CISA KEV status is false in the bundle, and no cited source states active exploitation.
Researcher notes
Key constraints are important: the affected set is limited to ASA 9.16.1 and FTD 7.0.0, exploitation requires an established IPsec connection or MITM position, and successful exploitation does not compromise encrypted data. No exploit-in-the-wild evidence is provided in the source bundle.
Mitigation direction
- Check Cisco's advisory for fixed releases, workarounds, and upgrade guidance.
- Inventory ASA and FTD deployments for versions 9.16.1 and 7.0.0.
- Prioritize remediation for internet-facing or business-critical IPsec VPN devices.
- Restrict IPsec connectivity to expected peers and networks where operationally feasible.
- Plan maintenance windows because remediation may require firewall or VPN changes.
Validation and detection
- Confirm exact ASA or FTD software version on each Cisco security appliance.
- Identify whether affected devices terminate active IPsec connections.
- Review monitoring for unexpected reloads or availability interruptions.
- Verify remediation status against Cisco's advisory before closing the finding.
- Document devices that are not on the two affected releases as out of scope.
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
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ATT&CK lookup starting points
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CWE-617: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-1422 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 7.7 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/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:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H3.14Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.7HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20210715 Cisco Adaptive Security Appliance Software Release 9.16.1 and Cisco Firepower Threat Defense Software Release 7.0.0 IPsec 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.
Reachable Assertion
Reachable Assertion represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.