CVE-2020-3580Known exploitationPublic exploitNetwork attack vector

Browser-script execution via unescaped SAML response

Published Oct 21, 2020 · Updated Oct 21, 2025

XSS in Cisco ASA and FTD web services allows remote attackers to execute arbitrary browser scripts via crafted links. The /+CSCOE+/saml/sp/acs endpoint reflects the SAMLResponse form parameter into HTML without neutralizing injected markup. Exploitation requires an affected AnyConnect or WebVPN configuration and user interaction, exposing browser-based information rather than granting appliance command execution.

CVSS severity6.1
Medium
EPSS probability85.58%
Next 30 days · Nov 1, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

XSS in Cisco ASA and FTD web services allows remote attackers to execute arbitrary browser scripts via crafted links. The /+CSCOE+/saml/sp/acs endpoint reflects the SAMLResponse form parameter into HTML without neutralizing injected markup. Exploitation requires an affected AnyConnect or WebVPN configuration and user interaction, exposing browser-based information rather than granting appliance command execution.

The record

CVE
CVE-2020-3580
Published
Oct 21, 2020
Updated
Oct 21, 2025
Vendor
Cisco
Product
Cisco Adaptive Security Appliance (ASA) Software
Classifications
CWE-79, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 21, 2020CVE publishedPublication date reported by the CVE source.
  2. Oct 21, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Cisco · Cisco Adaptive Security Appliance (ASA) Softwareversion=n/a

Published CVSS scores

6.1CiscoCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsShadowserver observations through Sep 28, 2026. Gaps indicate unavailable data.
Sep 22, 2026Sep 28, 2026
View daily counts
Reporting dayUnique IPs
Sep 22, 20267
Sep 23, 20261
Sep 24, 20265
Sep 25, 20262
Sep 26, 2026Unavailable
Sep 27, 20261
Sep 28, 20262
Latest reporting daySep 28, 2026
Latest daily unique IPs2
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1204.001Malicious Link

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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