CVE-2020-3452: in the CISA KEV catalogue

Cisco ASA and FTD Read-Only Path Traversal Vulnerability. CISA added CVE-2020-3452 to the Known Exploited Vulnerabilities catalogue on 2021-11-03 with a default due date of 2022-05-03. Known ransomware campaign use: Unknown. Forensic triage flag: No.

Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) contain an improper input validation vulnerability when HTTP requests process URLs. An attacker could exploit this vulnerability by sending a crafted HTTP request containing directory traversal character sequences to an affected device. A successful exploit could allow the attacker to view arbitrary files within the web services file system on the targeted device. (CISA description)

Vendor / product: Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD)
CWE: CWE-20
CISA required action: Apply updates per vendor instructions.
EPSS: 100%, percentile 99 (scored 2026-11-03)

EPSS puts nearly every time in 100 odds (100%) on exploitation activity being observed in the next 30 days. Its score is higher than or equal to that of 99% of scored CVEs. This is a model estimate about exploitation anywhere, not about your environment.

Vendor and reference links (from CISA)

https://nvd.nist.gov/vuln/detail/CVE-2020-3452

Your own deadline under CISA BOD 26-04 depends on exposure, automatability and technical impact: work it out with the BOD 26-04 calculator.

Data dates. CISA KEV catalogue version 2026.11.03, released 2026-11-03, 1,767 entries (checked 2026-11-03). EPSS model v2026.06.15, scored 2026-11-03, 399,388 CVEs. Sources: CISA and FIRST (EPSS by FIRST; scores generated by Empirical Security). Copied to our own database and refreshed automatically; if a refresh fails, the previous copy keeps serving with its own date.

Frequently asked questions

Is CVE-2020-3452 in the CISA KEV catalogue?

Yes. CISA added CVE-2020-3452 (Cisco ASA and FTD Read-Only Path Traversal Vulnerability) to the Known Exploited Vulnerabilities catalogue on 2021-11-03. CISA's default due date for it is 2022-05-03.

Is CVE-2020-3452 used in ransomware attacks?

CISA marks known ransomware campaign use as Unknown for CVE-2020-3452. That means CISA lacks confirmation, not that ransomware groups do not use it.

What should I do about CVE-2020-3452?

CISA's required action: Apply updates per vendor instructions.

Sources

CISA, Known Exploited Vulnerabilities Catalog (accessed 2026-11-03)
FIRST, Exploit Prediction Scoring System (EPSS) (EPSS by FIRST; scores generated by Empirical Security)
NVD record for CVE-2020-3452