Cisco ThousandEyes Endpoint Agent for Windows Arbitrary File Delete Vulnerabilities

TL;DR 📌

• Multiple vulnerabilities in the update process of Cisco ThousandEyes Endpoint Agent for Windows could allow an authenticated, local attacker to delete arbitrary files on an affected device. These vulnerabilities are due to improper access controls on files that are in the local file system. An attacker could exploit these vulnerabilities by using a symbolic link to perform an agent upgrade…
• No fixed release listed yet; apply mitigations and monitor.
• Workarounds are documented in the advisory.
• CVEs: CVE-2025-20259.

What happened 🕵️‍♂️

Multiple vulnerabilities in the update process of Cisco ThousandEyes Endpoint Agent for Windows could allow an authenticated, local attacker to delete arbitrary files on an affected device.

These vulnerabilities are due to improper access controls on files that are in the local file system. An attacker could exploit these vulnerabilities by using a symbolic link to perform an agent upgrade that redirects the delete operation of any protected file. A successful exploit could allow the attacker to delete arbitrary files from the file system of the affected device.

Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities.

Affected products 🖥️

At the time of publication, these vulnerabilities affected Cisco ThousandEyes Endpoint Agent for Windows, regardless of device configuration.

For information about which Cisco software releases were vulnerable at the time of publication, see the Fixed Software ["#fs"] section of this advisory. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.

Fixed software 🔧

Upgrade to the first fixed release in your train (or later):

Workarounds 🧯

There are no workarounds that address these vulnerabilities.

Risk in context 🎯

Use vendor CVSS for prioritization. Consider exposure and asset criticality.

Fast facts ⚡

• Advisory: cisco-sa-te-endagent-filewrt-zNcDqNRJ
• Initial release: 2025-06-04T16:00:00 UTC
• Last updated: 2025-06-04T16:00:00 UTC

For leadership 🧭

Executive summary. Risk is Medium (CVSS 5.3) for Cisco, Cisco ThousandEyes Endpoint Agent. Vendor fixes are available; prioritize upgrade within 30 days based on environment risk.

Why it matters (exposure drivers):

• Potential service impact and security exposure depend on deployment topology and access paths.
• Treat internet-exposed or multi-tenant management nodes as higher risk.
• Ensure monitoring for abnormal auth/config events until upgrades complete.

Remediation & timing:

• Upgrade to the first fixed release per the table above; schedule an approved change window within 30 days.
• Change risk: low-to-moderate (standard vendor patch). Validate backups and rollback plan.

Now / Next / Later:

• Now: Confirm exposure, identify affected versions, and enable monitoring/alerts.
• Next: Patch according to the fixed software table; verify service health post-change.
• Later: Add control checks to build pipeline/CMDB to block drift to vulnerable trains.