Vulnerability-Lookup

GHSA-RX7M-QPRJ-P54H

Vulnerability from github – Published: 2026-10-05 15:32 – Updated: 2026-10-05 15:32

Details

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.

Severity

6.6 (Medium)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

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JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-77804"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-367"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-05T13:16:54Z",
    "severity": "MODERATE"
  },
  "details": "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. Successful exploitation requires the user to initiate the certificate trust operation and approve the elevation prompt.",
  "id": "GHSA-rx7m-qprj-p54h",
  "modified": "2026-10-05T15:32:22Z",
  "published": "2026-10-05T15:32:22Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-77804"
    },
    {
      "type": "WEB",
      "url": "https://docs.telerik.com/fiddler/knowledge-base/kb-security-root-certificate-installation-toctou-cve-2026-77804"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-77804 (GCVE-0-2026-77804)

Vulnerability from cvelistv5 – Published: 2026-10-05 12:40 – Updated: 2026-10-06 17:49

Title

Time-of-check Time-of-use (TOCTOU) Race Condition in Root Certificate Installation in Progress® Telerik® Fiddler® Classic

Summary

Severity

6.6 (Medium)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-06 17:49 UTC

CWE

CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition

Assigner

ProgressSoftware mitre root Scorecard

References

1 reference

URL	Tags
https://docs.telerik.com/fiddler/knowledge-base/k…	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
Progress Software	Progress® Telerik® Fiddler® Classic	Affected: 1.0.0 , < 6.0.20262.10021 (custom)

Credits

NATO Cyber Security Centre (NCSC)

Show details on NVD website

JSON

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                  },
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                "role": "CISA Coordinator",
                "timestamp": "2026-10-06T17:49:19.748248Z",
                "version": "2.0.3"
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    "state": "PUBLISHED"
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  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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GHSA-RX7M-QPRJ-P54H

CVE-2026-77804 (GCVE-0-2026-77804)

Tags

Sightings

Nomenclature

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