CVE-2021-1573
CVE-2021-1573 is a high-severity vulnerability in Cisco Adaptive Security Appliance with a CVSS 3.x base score of 8.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.
Key facts
- Severity: High (CVSS 3.x base score 8.6)
- CVSS v2: 7.1
- EPSS exploit prediction: 1% (67th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-787
- Affected product: Cisco Adaptive Security Appliance
- Published:
- Last modified:
Description
A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition. This vulnerability is due to improper input validation when parsing HTTPS requests. An attacker could exploit this vulnerability by sending a malicious HTTPS request to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
Frequently asked questions
- What is CVE-2021-1573?
- A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition. This vulnerability is due to improper input validation when parsing HTTPS requests. An attacker could exploit this vulnerability by sending a malicious HTTPS request to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
- How severe is CVE-2021-1573?
- CVE-2021-1573 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2021-1573 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2021-1573?
- CVE-2021-1573 primarily affects Cisco Adaptive Security Appliance. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2021-1573?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2021-1573 published?
- CVE-2021-1573 was published on 2022-01-11 and last updated on 2026-06-17.
References
Affected products (4)
- cpe:2.3:a:cisco:adaptive_security_appliance:*:*:*:*:*:*:*:*
- cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:*
- cpe:2.3:a:cisco:firepower_threat_defense:7.0.0:*:*:*:*:*:*:*
- cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
More vulnerabilities in Cisco Adaptive Security Appliance
- CVE-2021-40118 — High (CVSS 8.6): A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower…
- CVE-2021-40117 — High (CVSS 8.6): A vulnerability in SSL/TLS message handler for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower…
- CVE-2021-34793 — High (CVSS 8.6): A vulnerability in the TCP Normalizer of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense…
- CVE-2020-3572 — High (CVSS 8.6): A vulnerability in the SSL/TLS session handler of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower…
- CVE-2020-3529 — High (CVSS 8.6): A vulnerability in the SSL VPN negotiation process for Cisco Adaptive Security Appliance (ASA) Software and Cisco…
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