FIDDLER DOWNLOAD & SETUP SKILL · CVE-2026-104657 · AI agents & MCP
FIX → current copy in telerik/fiddler-agent-tools ✓ verified
The Fiddler Download and Setup Skill fails to verify the integrity of the release package it fetches on Linux, macOS, and Windows. An attacker who tampers with that package can run their own code when a user runs the skill, and on macOS a local process can swap the staged package for a root-privileged install.
first public Nov 6, 2026 · 2 sources
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Teams that downloaded the Progress Telerik Fiddler Download & Setup Skill (fiddler-download-setup) before October 5, 2026 and run it in a coding agent on Linux, macOS or Windows. The skill fetches the Fiddler Everywhere installer without checking it against the manifest SHA-512 or a signature, so an attacker who compromises or influences a release component could run code when the skill is used. On macOS the package sits at a predictable /tmp path and installs as admin, so a malicious package could get root after you approve the prompt, and a local process could swap it while the skill waits. Teams that never used this skill, or use a current copy, can skip it.
Not affected if current-skill-copy, manual-install, skill-not-installed
Who cares ai-skills, fiddler, linux, macos, progress, telerik, windows
Missing integrity verification in the Progress Software Fiddler Download and Setup Skill on Linux, macOS, and Windows which allows an attacker to compromise or influence a release component and execute attacker-controlled code when a user runs the skill. On macOS, the skill stages the package at a predictable path and installs it with administrator privileges, which may allow code execution with root privileges after user approval. A local process may also replace the staged macOS package while the skill waits for approval.
This page as .md · .json · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
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Upgrade to current copy in telerik/fiddler-agent-tools