CVE-2020-3452: Cisco ASA and FTD Read-Only Path Traversal Vulnerability

criticalknown exploitedpublic exploitCVE-2020-3452

Actively exploited. At least one CVE in this advisory is listed in the CISA Known Exploited Vulnerabilities catalog — exploitation has been observed in the wild. Treat remediation as urgent.

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.

CSIRTS triage

vendor: Cisco product: Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD)Path traversal

What: An improper input validation vulnerability allows an attacker to view arbitrary files within the web services file system.
Who is affected: Deployments of Cisco ASA and FTD devices.
Urgency: Remediation is urgent due to active exploitation and critical severity.
Action: Apply the latest patches for Cisco ASA and FTD.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: CISA Known Exploited Vulnerabilities (US · database · site)
Severity: critical
Published: 2021-11-03
Exploitation: Observed in the wild (CISA KEV)

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

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Exploitation confirmedCVE-2020-3452Already exploited in the wild (CISA KEV) — the prediction phase is over. Patch now. Riskier than 99.9% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2020-3452	coverage & exploitation status	NVD · CVE.org

Recent advisories for Cisco ASA and

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

highexploitedAL26-018 - Vulnerability affecting Cisco ASA and Secure Firewall Threat Defense Software Remote Access SSL VPN…cccs · 2026-08-13
unknownexploitedNCSC-2026-0295 [1.00] [M/H] Vulnerability patched in Cisco Secure Firewall ASA and FTD softwarencsc-nl · 2026-08-12
highexploited[NEW] [high] Cisco ASA (Adaptive Security Appliance) and Secure Firewall Threat Defense: Vulnerability enables…cert-bund · 2026-08-12
highexploitedCVE-2026-20349: A vulnerability in the Remote Access SSL VPN service for Cisco Secure Firewall Adaptive Securi…nvd · 2026-08-11
criticalexploitedCVE-2026-20349: Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FT…cisa-kev · 2026-08-11
criticalexploitedCVE-2025-20362: Cisco Secure Firewall Adaptive Security (ASA) Appliance and Secure Firewall Threat Defense (FT…cisa-kev · 2025-09-25

CVE-2020-3452: Cisco ASA and FTD Read-Only Path Traversal Vulnerability

CSIRTS triage

Details

Exploitation outlook

Referenced CVEs

Recent advisories for Cisco ASA and

More from CISA Known Exploited Vulnerabilities