HOMEVULNERABILITIESCVE-2020-13661
HIGH

CVE-2020-13661

NVD-CWE-noinfoPublished: November 5, 2020· Updated: Jun 17, 2026

8.8
CVSS v3.1

Official Description

Telerik Fiddler through 5.0.20202.18177 allows attackers to execute arbitrary programs via a hostname with a trailing space character, followed by --utility-and-browser --utility-cmd-prefix= and the pathname of a locally installed program. The victim must interactively choose the Open On Browser option. Fixed in version 5.0.20204.

NVD Source

Technical Analysis

CVE-2020-13661 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation does not require any privileges, though user interaction (Required) is needed, which slightly reduces the risk of mass automated attacks.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 8.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionRequired
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected Vendors & Products

telerik1 product(s)
fiddler
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://www.telerik.com/support/whats-new/fiddler/release-history/fiddler-v5.0.20204
ADVISORYhttps://www.telerik.com/support/whats-new/release-history
ADVISORYhttps://www.telerik.com/support/whats-new/fiddler/release-history/fiddler-v5.0.20204
ADVISORYhttps://www.telerik.com/support/whats-new/release-history

All References (6)

→
https://www.nagenrauft-consulting.com/blog/Not Applicable
→
https://www.telerik.com/support/whats-new/fiddler/release-history/fiddler-v5.0.20204Release Notes · Vendor Advisory
→
https://www.telerik.com/support/whats-new/release-historyRelease Notes · Vendor Advisory
→
https://www.nagenrauft-consulting.com/blog/Not Applicable
→
https://www.telerik.com/support/whats-new/fiddler/release-history/fiddler-v5.0.20204Release Notes · Vendor Advisory
→
https://www.telerik.com/support/whats-new/release-historyRelease Notes · Vendor Advisory

Quick Facts

CVE IDCVE-2020-13661
CVSS Score8.8 / 10
SeverityHIGH
WeaknessNVD-CWE-noinfo
CISA KEVNo
Affected1 vendor(s)
PublishedNov 5, 2020

Related CVEs (NVD-CWE-noinfo)

CVE-2026-46798
10.0
CVE-2012-1002
10.0
CVE-2012-3859
10.0
CVE-2012-1484
10.0
CVE-2012-5692
10.0
CVE-2009-3091
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2020-13661 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
← All Vulnerabilities·Search for CVE-2020-13661·NVD