CVE-2021-1267Network attack vector

Authenticated resource exhaustion via recursive XML entities

Published Jan 13, 2021 · Updated Nov 12, 2024

XML entity expansion in Cisco Firepower Management Center before 6.6.1 allows remote authenticated users to exhaust device resources. The dashboard widget parser expands crafted recursive XML entities without adequate restrictions, driving memory and CPU utilization upward. Low-privileged access to create an XML-based widget is required, and successful exploitation interrupts the management service through resource exhaustion.

CVSS severity4.3
Medium
EPSS probability1.01%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

XML entity expansion in Cisco Firepower Management Center before 6.6.1 allows remote authenticated users to exhaust device resources. The dashboard widget parser expands crafted recursive XML entities without adequate restrictions, driving memory and CPU utilization upward. Low-privileged access to create an XML-based widget is required, and successful exploitation interrupts the management service through resource exhaustion.

The record

CVE
CVE-2021-1267
Published
Jan 13, 2021
Updated
Nov 12, 2024
Vendor
ClamAV
Product
Cisco Firepower Management Center
Classifications
CWE-776, CAPEC-197, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 13, 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 Firepower Management Centerversion=n/a

Published CVSS scores

4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
4.3Cisco Systems, Inc.CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:X/RL:X/RC:X
4.0NIST NVDAV:N/AC:L/Au:S/C:N/I:N/A:P

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-776Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')
CAPEC-197Exponential Data Expansion
T1499.004Application or System Exploitation

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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