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Vendor Workaround
Carefully review every User Account Control elevation prompt raised by Fiddler Classic and confirm that it refers to the expected executable before approving it. Alternatively, avoid launching external tools from the Fiddler Classic application, such as the Windows 8 Loopback Exemptions tool or the machine store certificate trust tool.
Tracking
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Mon, 05 Oct 2026 16:30:00 +0000
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Mon, 05 Oct 2026 13:00:00 +0000
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| Description | In Progress® Telerik® Fiddler® Classic for Windows, versions prior to v6.0.20262.10021, the integrity check applied to the external helper tools launched by the application is insufficient. Before executing a helper tool, the application only verifies that the file carries a valid Authenticode signature whose certificate subject name matches a broad allow list of publisher name fragments, rather than verifying that the file is the specific executable shipped with that version of the product. A local threat actor with low privileges who replaces one of these helper executables with any other validly signed binary from an allow-listed publisher can cause the substituted binary to be executed by the application, including with Administrator privileges for the tools that request elevation, resulting in privilege escalation and execution of unintended code. Successful exploitation requires the user to launch the affected external tool and to approve the elevation prompt without noticing that it refers to a different executable. | |
| Title | Weak Executable Signature Verification Vulnerability in Progress® Telerik® Fiddler® Classic | |
| Weaknesses | CWE-347 | |
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| Metrics |
cvssV3_1
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Subscriptions
No data.
Status: PUBLISHED
Assigner: ProgressSoftware
Published:
Updated: 2026-10-05T15:26:04.778Z
Reserved: 2026-08-21T13:37:36.679Z
Link: CVE-2026-77805
Updated: 2026-10-05T13:57:07.714Z
Status : Received
Published: 2026-10-05T13:16:54.740
Modified: 2026-10-05T16:17:16.293
Link: CVE-2026-77805
No data.
OpenCVE Enrichment
Updated: 2026-10-05T15:15:08Z
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CWE-347
Improper Verification of Cryptographic Signature