CVE-2026-20161

Low-privilege arbitrary file overwrite via symlink following

Published Apr 15, 2026 · Updated Apr 15, 2026

Improper link resolution in the Cisco ThousandEyes Enterprise Agent CLI allows local users to overwrite arbitrary files through a symlink. The Linux Package CLI follows a symbolic link placed at a specific local path without enforcing the target file's access controls, redirecting a privileged write. Only the Linux Package installation type is exposed, regardless of device configuration; virtual appliances and Docker deployments are not affected.

CVSS severity5.5
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper link resolution in the Cisco ThousandEyes Enterprise Agent CLI allows local users to overwrite arbitrary files through a symlink. The Linux Package CLI follows a symbolic link placed at a specific local path without enforcing the target file's access controls, redirecting a privileged write. Only the Linux Package installation type is exposed, regardless of device configuration; virtual appliances and Docker deployments are not affected.

The record

CVE
CVE-2026-20161
Published
Apr 15, 2026
Updated
Apr 15, 2026
Vendor
ClamAV
Product
ThousandEyes Enterprise Agent
Classifications
CWE-59
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Agent 4.0
  2. Affected versionversion=Agent 4.1
  3. Affected versionversion=Agent 4.2
  4. Affected versionversion=Agent 4.4.2
  5. Affected versionversion=Agent 4.4.3
  6. Affected versionversion=Agent 4.4.4
  7. Affected versionversion=Agent 5.0
  8. Affected versionversion=Agent 5.1
  9. Affected versionversion=Agent 5.1.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

ClamAV · ThousandEyes Enterprise Agentversion=Agent 4.0; version=Agent 4.1; version=Agent 4.2; version=Agent 4.4.2; version=Agent 4.4.3; version=Agent 4.4.4; version=Agent 5.0; version=Agent 5.1; version=Agent 5.1.2

Published CVSS scores

5.5Cisco Systems, Inc.CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N/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.

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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-59Improper Link Resolution Before File Access ('Link Following')

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo