CVE-2021-1456Network attack vector

Browser script execution via insufficient input validation

Published Apr 29, 2021 · Updated Nov 8, 2024

Reflected XSS in affected Cisco Firepower Management Center releases allows remote attackers to execute script via a crafted link. The web-based management interface returns insufficiently validated link input to a user's browser, where it executes in the interface context. Exploitation requires an interface user to click the link and exposes browser-based information or permits actions in that user's context.

CVSS severity4.8
Medium
EPSS probability0.62%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in affected Cisco Firepower Management Center releases allows remote attackers to execute script via a crafted link. The web-based management interface returns insufficiently validated link input to a user's browser, where it executes in the interface context. Exploitation requires an interface user to click the link and exposes browser-based information or permits actions in that user's context.

The record

CVE
CVE-2021-1456
Published
Apr 29, 2021
Updated
Nov 8, 2024
Vendor
ClamAV
Product
Cisco Firepower Management Center
Classifications
CWE-79, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 29, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 8, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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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?

ClamAV · Cisco Firepower Management Centerversion=n/a

Published CVSS scores

3.5NIST NVDAV:N/AC:M/Au:S/C:N/I:P/A:N
4.8Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

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Your stack

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