CVE-2021-1594Network attack vector

Root command execution via REST API validation

Published Oct 6, 2021 · Updated Nov 7, 2024

Command injection in the REST API of Cisco Identity Services Engine allows remote attackers to execute arbitrary commands as root. Specific REST API endpoints fail to validate intercepted and modified internode communications before command execution. Exploitation is unauthenticated but requires a distributed deployment and a man-in-the-middle position capable of decrypting HTTPS traffic between separate ISE personas.

CVSS severity7.5
High
EPSS probability1.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in the REST API of Cisco Identity Services Engine allows remote attackers to execute arbitrary commands as root. Specific REST API endpoints fail to validate intercepted and modified internode communications before command execution. Exploitation is unauthenticated but requires a distributed deployment and a man-in-the-middle position capable of decrypting HTTPS traffic between separate ISE personas.

The record

CVE
CVE-2021-1594
Published
Oct 6, 2021
Updated
Nov 7, 2024
Vendor
ClamAV
Product
Cisco Identity Services Engine
Classifications
CWE-266, CWE-78, T1059, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 6, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 7, 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 Identity Services Engineversion=n/a

Published CVSS scores

7.5Cisco Systems, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X
8.1NISTCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
9.3NISTAV:N/AC:M/Au:N/C:C/I:C/A:C

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-266Incorrect Privilege Assignment
CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059Command and Scripting Interpreter
T1557Adversary-in-the-Middle

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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