{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-77804", "assignerOrgId": "f9fea0b6-671e-4eea-8fde-31911902ae05", "state": "PUBLISHED", "assignerShortName": "ProgressSoftware", "dateReserved": "2026-08-21T13:37:35.057Z", "datePublished": "2026-10-05T12:40:26.811Z", "dateUpdated": "2026-10-06T17:49:23.338Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "f9fea0b6-671e-4eea-8fde-31911902ae05", "shortName": "ProgressSoftware", "dateUpdated": "2026-10-05T12:40:26.811Z"}, "title": "Time-of-check Time-of-use (TOCTOU) Race Condition in Root Certificate Installation in Progress\u00ae Telerik\u00ae Fiddler\u00ae Classic", "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-367", "description": "CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition", "type": "CWE"}]}], "impacts": [{"capecId": "CAPEC-29", "descriptions": [{"lang": "en", "value": "CAPEC-29 Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions"}]}], "affected": [{"vendor": "Progress Software", "product": "Progress\u00ae Telerik\u00ae Fiddler\u00ae Classic", "platforms": ["Windows"], "versions": [{"status": "affected", "version": "1.0.0", "lessThan": "6.0.20262.10021", "versionType": "custom"}], "defaultStatus": "unaffected"}], "descriptions": [{"lang": "en", "value": "In Progress\u00ae Telerik\u00ae Fiddler\u00ae 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. 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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. 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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.", "supportingMedia": [{"type": "text/html", "value": "In Progress\u00ae Telerik\u00ae Fiddler\u00ae 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. 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