{
    "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® Telerik® Fiddler® 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® Telerik® Fiddler® 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® 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.",
                    "supportingMedia": [
                        {
                            "type": "text/html",
                            "base64": false,
                            "value": "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."
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://docs.telerik.com/fiddler/knowledge-base/kb-security-root-certificate-installation-toctou-cve-2026-77804",
                    "tags": [
                        "vendor-advisory"
                    ]
                }
            ],
            "metrics": [
                {
                    "format": "CVSS",
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "GENERAL"
                        }
                    ],
                    "cvssV3_1": {
                        "version": "3.1",
                        "attackVector": "LOCAL",
                        "attackComplexity": "LOW",
                        "privilegesRequired": "LOW",
                        "userInteraction": "REQUIRED",
                        "scope": "UNCHANGED",
                        "confidentialityImpact": "HIGH",
                        "integrityImpact": "HIGH",
                        "availabilityImpact": "NONE",
                        "baseSeverity": "MEDIUM",
                        "baseScore": 6.6,
                        "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N"
                    }
                }
            ],
            "workarounds": [
                {
                    "lang": "en",
                    "value": "Trust the Fiddler Classic certificate only in the Current User certificate store. When the application asks to install the certificate in the Local Computer (local machine) store, choose No. If a machine-wide trust is required, export the certificate to a file and import that file into the Local Computer Trusted Root Certification Authorities store manually.",
                    "supportingMedia": [
                        {
                            "type": "text/html",
                            "base64": false,
                            "value": "<div>Trust the Fiddler Classic certificate only in the <b>Current User</b> certificate store. When the application asks to install the certificate in the <b>Local Computer</b> (local machine) store, choose <b>No</b>. If a machine-wide trust is required, export the certificate to a file and import that file into the Local Computer Trusted Root Certification Authorities store manually.</div>"
                        }
                    ]
                }
            ],
            "credits": [
                {
                    "lang": "en",
                    "value": "NATO Cyber Security Centre (NCSC)",
                    "type": "finder"
                }
            ],
            "source": {
                "discovery": "EXTERNAL"
            },
            "x_generator": {
                "engine": "Vulnogram 0.2.0"
            }
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-10-06T17:49:19.748248Z",
                                "id": "CVE-2026-77804",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "Technical Impact": "total"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-10-06T17:49:23.338Z"
                }
            }
        ]
    }
}