CVE-2021-1266Network attack vector

Authenticated service interruption via crafted request logging

Published Feb 4, 2021 · Updated Nov 8, 2024

Denial of service in the Cisco MSX REST API before 3.10.0 allows remote authenticated users to interrupt service via crafted requests. The request-logging path consumes excessive resources while recording a flood of crafted API requests. Valid API credentials and sustained network access are required; successful exploitation interrupts availability without reading or modifying data.

CVSS severity4.3
Medium
EPSS probability1.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Cisco MSX REST API before 3.10.0 allows remote authenticated users to interrupt service via crafted requests. The request-logging path consumes excessive resources while recording a flood of crafted API requests. Valid API credentials and sustained network access are required; successful exploitation interrupts availability without reading or modifying data.

The record

CVE
CVE-2021-1266
Published
Feb 4, 2021
Updated
Nov 8, 2024
Vendor
ClamAV
Product
Cisco Managed Services Accelerator
Classifications
CWE-400, T1499.003
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 4, 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 privilegesauthenticated

What is affected?

ClamAV · Cisco Managed Services Acceleratorversion=n/a

Published CVSS scores

4.3CiscoCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:X/RL:X/RC:X

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.

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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-400Uncontrolled Resource Consumption
T1499.003Application Exhaustion Flood

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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