Missing Integrity Verification in Progress Software Fiddler Download & Setup Skill
Copies of the Fiddler Download & Setup Skill downloaded before October 5, 2026 are affected, and the skill is not versioned. Progress says the currently published skill has the issue addressed.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 8.3.0
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. Affects copies of the Fiddler Download & Setup Skill downloaded before October 5, 2026; the skill is not versioned. On macOS, the skill stages the package at a predictable path and installs it with administrator privileges.
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 21/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: total
Summary
The Progress Software Fiddler Download and Setup Skill on Linux, macOS, and Windows lacks integrity verification, so an attacker can tamper with a release component and run attacker-controlled code when a user runs the skill. An attacker can reach this remotely, without logging in, but a user must run the skill and, on macOS, approve the installation, which may allow code execution with root privileges.
Read the original description
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.
cve.now Index
- Exploitation0/40No signal
- Exposure12/25Specific setups only, reachable over the network without a login
- Reach?/20Unknown. No tracked technology or package matched
- Severity8.5/10CVSS 7.5, total technical impact per CISA
- No patch0/5No signal
What would change the score
- Would score about 71 if added to CISA KEV
- Would score about 66 if CISA's SSVC rates exploitation active
What to do
Check whether your setup matches what the bug needs.
Affects copies of the Fiddler Download & Setup Skill downloaded before October 5, 2026; the skill is not versioned. On macOS, the skill stages the package at a predictable path and installs it with administrator privileges.Upgrade to a fixed version: 8.3.0.
Workaround: Do not run an existing copy of the affected skill; install Fiddler manually from the official distribution source and verify the artifact's publisher signature and checksum.
Timeline
- CVE published
- First seen by cve.now
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- Progress Software Fiddler Download & Setup Skill
fixed in 8.3.0
Evidence 1
- Advisory
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-104657
Is CVE-2026-104657 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
The skill could deliver attacker-controlled code that runs when a user invokes it. On macOS, the skill stages its package at a predictable /tmp path and installs it with administrator privileges, so a malicious package could run with root privileges after the user approves the prompt.Source: telerik.com
Which versions are affected by CVE-2026-104657?
Fiddler Download & Setup Skill: before 8.3.0.Source: cve.now feed data
Am I affected, and how do I check?
The issue affects copies of the skill downloaded before October 5, 2026, because the skill is not versioned, so the download date of a copy is the main thing to check. On macOS, the predictable /tmp/FiddlerEverywhere.pkg path is part of the affected behavior.Source: telerik.com
How do I fix CVE-2026-104657?
Do not run an existing copy of the affected skill. Install Fiddler manually from the official distribution source and verify the artifact's publisher signature and checksum.Source: telerik.com
Why do the sources disagree?
The sources conflict on the attack requirements. The description refers to an authenticated vector, but the vector string lists PR:N, which means no privileges are required. The published fix is also not tied to a listed fixed version, since the version list is empty, while the vendor text says the issue is addressed in the currently published skill.Source: telerik.com