CVE-2021-1253Network attack vector

Persistent XSS via insufficient web-field validation

Published Jan 20, 2021 · Updated Nov 12, 2024

Persistent XSS in Cisco Data Center Network Manager before 11.5(1) allows remote authenticated users to execute script in another user's browser. The web interface stores malicious data inserted into a specific field without sufficient input validation and later renders it to another user. Network-operator privileges and victim interaction are required; execution can alter browser-visible data or expose sensitive browser information.

CVSS severity6.5
Medium
EPSS probability0.61%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Persistent XSS in Cisco Data Center Network Manager before 11.5(1) allows remote authenticated users to execute script in another user's browser. The web interface stores malicious data inserted into a specific field without sufficient input validation and later renders it to another user. Network-operator privileges and victim interaction are required; execution can alter browser-visible data or expose sensitive browser information.

The record

CVE
CVE-2021-1253
Published
Jan 20, 2021
Updated
Nov 12, 2024
Vendor
ClamAV
Product
Cisco Data Center Network Manager
Classifications
CWE-20, CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 20, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 12, 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 privilegesauthenticated

What is affected?

ClamAV · Cisco Data Center Network Managerversion=n/a

Published CVSS scores

3.5NIST NVDAV:N/AC:M/Au:S/C:N/I:P/A:N
5.9Cisco Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
6.5Cisco Systems, Inc. CNACVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript/JScript

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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