Security readout for executives and security teams
Plain-English summary
CVE-2021-1493 affects Cisco ASA and Firepower Threat Defense web services. An authenticated remote attacker could trigger a buffer overflow, potentially causing the device to reload and interrupt firewall or security service availability. The source also notes possible disclosure of data fragments.
Executive priority
Prioritize based on exposure of internet-facing or broadly reachable security appliances. Authenticated access reduces likelihood, but a successful denial of service on firewall infrastructure can disrupt business connectivity and security operations.
Technical view
The issue is insufficient boundary checking in the web services interface, classified as CWE-120. The CVSS 3.1 score is 8.5: network reachable, low complexity, low privileges required, no user interaction, changed scope, low confidentiality impact, and high availability impact.
Likely exposure
Exposure is most relevant where Cisco ASA or FTD web services are enabled and reachable by authenticated users. The provided sources do not include affected version ranges, so teams must verify exact product builds against Cisco guidance.
Exploitation context
The provided bundle does not show CISA KEV listing or active exploitation evidence. Exploitation requires authentication and a malicious HTTP request to the affected web services interface. Successful exploitation may disclose fragments or cause reload-based denial of service.
Researcher notes
Key unresolved details are exact affected versions and fixed releases, which are not present in the supplied bundle. Treat Cisco's advisory as authoritative for product matrices, caveats, and remediation status. Avoid assuming unauthenticated exploitability.
Mitigation direction
- Check Cisco's advisory for affected releases and fixed software guidance.
- Upgrade affected Cisco ASA or FTD systems according to vendor guidance.
- Restrict web services access to trusted networks and necessary authenticated users.
- Review administrative and VPN-related accounts with web services access.
- Monitor perimeter devices for unexpected reloads or availability instability.
Validation and detection
- Inventory Cisco ASA and FTD deployments and enabled web services.
- Compare running software versions with Cisco's advisory coverage.
- Confirm web services are not exposed beyond required trusted access paths.
- Review device logs for reloads or suspicious authenticated HTTP activity.
- Verify remediation by rechecking version and access-control posture.
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-120: 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-2021-1493 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
- 8.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/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:L/I:N/A:H3.14.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.5HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20210428 Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Web Services Buffer Overflow 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.
