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Fencer Vulns
medium 6.1

CVE-2020-3580 kev+ ransomware in the critical feed json

Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Web Services Interface Cross-Site Scripting Vulnerabilities

published 2020-10-21 6 y ago modified 2026-08-11 2 mo ago also EUVD-2020-24851

cvss
6.1
version 3.1, CNA
cisa kev
Exploited
added 2021-11-03, used in ransomware
epss
85.6%
EPSS 85.6% chance of exploitation in 30 days, percentile 99.7%
public exploits
0
none known, plus a Nuclei check

Summary

Multiple vulnerabilities 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 conduct cross-site scripting (XSS) attacks against a user of the web services interface of an affected device. The vulnerabilities are due to insufficient validation of user-supplied input by the web services interface of an affected device. An attacker could exploit these vulnerabilities by persuading a user of the interface to click a crafted link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the interface or allow the attacker to access sensitive, browser-based information. Note: These vulnerabilities affect only specific AnyConnect and WebVPN configurations. For more information, see the Vulnerable Products section.

Patch / fix

cisa required action Apply updates per vendor instructions.

  • cisco secure_firewall_threat_defense 6.4.0.12, 6.6.4, 6.7.0.2
  • cisco adaptive_security_appliance_software 9.8.4.34, 9.9.2.85, 9.12.4.13, 9.13.1.21, 9.14.2.8, 9.15.1.15

Timeline

  1. Published
  2. Added to CISA KEV
  3. CISA patch deadline
  4. CISA SSVC: exploitation active

Known exploited

Added
5 y ago
Patch by
2022-05-03 (4 y ago)
Ransomware
Known to be used in ransomware campaigns
Required action
Apply updates per vendor instructions.
Vendor, product
Cisco, Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD)
CISA name
Cisco ASA and FTD Cross-Site Scripting (XSS) Vulnerability

ATT&CK techniques

How it is exploited and what it leads to, in MITRE ATT&CK terms.

  • T1204.001 Malicious Link exploitation
  • T1059 Command and Scripting Interpreter primary impact
  • T1217 Browser Information Discovery secondary impact

kev release 2025-07-28, att&ck v16.1. KEV to ATT&CK mappings by the MITRE Center for Threat-Informed Defense (Mappings Explorer, Apache-2.0). © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. Terms of use

CISA SSVC

Exploitation
Active, exploited in the wild
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

85.58% chance of exploitation in the next 30 days, higher than 99.7% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • Nuclei template Cisco ASA/FTD Software - Cross-Site Scripting nuclei detection template

CVSS scores

assigned by version score vector
CNA 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 2.6 AV:N/AC:H/Au:N/C:N/I:P/A:N

Affected products

  • Cisco Cisco Adaptive Security Appliance (ASA) Software

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.