{"id":"CVE-2026-77804","revision":"3abbe0b647d14b50ba18e0a9dc5677d0","records":[{"revision":"3abbe0b647d14b50ba18e0a9dc5677d0","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-77804","aliases":[],"title":"Time-of-check Time-of-use (TOCTOU) Race Condition in Root Certificate Installation in Progress® Telerik® Fiddler® Classic","description":"In Progress® Telerik® Fiddler® Classic for Windows, versions prior to v6.0.20262.10021, a time-of-check time-of-use (TOCTOU) race condition exists in the installation of the HTTPS interception root certificate into the Local Computer certificate store. Fiddler writes the certificate to a temporary file in a user-writable location and then launches the external TrustCert helper application, which elevates and imports the certificate from that file. A local threat actor with low privileges who replaces the temporary file between the time it is written and the time the elevated helper reads it can cause an attacker-supplied root certificate to be installed in the Local Computer Trusted Root Certification Authorities store, enabling subsequent interception and modification of TLS-protected traffic on the machine. Successful exploitation requires the user to initiate the certificate trust operation and approve the elevation prompt.","state":0,"publishedAt":"2026-10-05T12:40:26.811+00:00","modifiedAt":"2026-10-06T17:49:23.338+00:00","affected":[{"ecosystem":"Vendor product","name":"Progress® Telerik® Fiddler® Classic","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Progress Software\",\n                    \"product\": \"Progress® Telerik® Fiddler® Classic\",\n                    \"platforms\": [\n                        \"Windows\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"status\": \"affected\",\n                            \"version\": \"1.0.0\",\n                            \"lessThan\": \"6.0.20262.10021\",\n                            \"versionType\": \"custom\"\n                        }\n                    ],\n                    \"defaultStatus\": \"unaffected\"\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N","score":6.6,"severity":"MEDIUM"}],"references":["https://docs.telerik.com/fiddler/knowledge-base/kb-security-root-certificate-installation-toctou-cve-2026-77804"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-77804","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-77804","identifiers":["CVE-2026-77804"]},"retained":false,"historicalAffected":[]}],"coverage":[]}