Security readout for executives and security teams
Plain-English summary
CVE-2021-1445 is a high-severity denial-of-service issue in Cisco ASA and FTD VPN web services. A remote unauthenticated attacker could cause an affected device to reload, interrupting VPN or firewall service availability. It only affects specific AnyConnect and WebVPN configurations.
Executive priority
Treat this as high priority for exposed VPN infrastructure because exploitation could disrupt remote access and security perimeter availability. Focus first on internet-facing ASA and FTD systems.
Technical view
Cisco describes multiple input-validation vulnerabilities in HTTPS request handling for ASA and FTD web services VPN features. Successful exploitation can reload the device, causing availability loss. The bundle lists CVSS 3.1 score 8.6 and CWE-787, but does not include exact affected version ranges.
Likely exposure
Organizations exposing Cisco ASA or FTD AnyConnect/WebVPN services are the likely exposure group. Exposure depends on the specific VPN configuration; not every ASA or FTD deployment is affected.
Exploitation context
The provided sources do not show CISA KEV listing or confirmed active exploitation. The issue is remotely reachable and unauthenticated where vulnerable VPN web services are exposed, increasing operational risk.
Researcher notes
Evidence is strongest for impact, access vector, and affected feature area. The bundle lacks exact version ranges, fixed releases, and workaround details, so validation should be anchored to the Cisco advisory rather than assumptions.
Mitigation direction
- Review Cisco advisory cisco-sa-asa-ftd-vpn-dos-fpBcpEcD for affected configurations and fixed releases.
- Prioritize remediation for internet-facing ASA or FTD VPN endpoints.
- Confirm whether AnyConnect or WebVPN features are enabled on exposed devices.
- Follow Cisco guidance; the provided bundle does not name a standalone workaround.
- Plan maintenance because remediation may require appliance software changes or reloads.
Validation and detection
- Inventory Cisco ASA and FTD appliances that provide VPN web services.
- Check whether each device uses affected AnyConnect or WebVPN configurations.
- Compare running software versions against Cisco advisory affected and fixed release details.
- Review device history for unexpected reloads or VPN service interruptions.
- Document non-affected devices with the configuration evidence used.
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-2021-1445 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 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/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:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H3.94Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.6HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/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 VPN Denial of Service VulnerabilitiesCVE 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.