CVE-2026-77804Medium· 6.6▾ SunlitIn 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 cer…
▾ Sunlit zone — Low / medium · no exploitation signal
impact 36.3 · likelihood 0 · exploitation 0
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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.
Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Connected by shared product, vendor, weakness, or advisory.
CVE-2026-77805High· 7.9In 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
CVE-2026-77803Low· 3.6In Progress® Telerik® Fiddler® Classic for Windows, versions prior to v6.0.20262.10021, front-end request desynchronization is possible in the proxy request forwarding component
CVE-2026-77802Medium· 6.3In Progress® Telerik® Fiddler® Classic for Windows, versions prior to v6.0.20262.10021, HTTP request smuggling is possible in the proxy request forwarding component
CVE-2026-23950High· 8.8node-tar,a Tar for Node.js, has a race condition vulnerability in versions up to and including 7.5.3
CVE-2026-92931High· 8.8CWE-918: Server-Side Request Forgery in the Progress @progress/sitefinity-nextjs-sdk npm package versions 15.1.8326 through 15.4.8637 may allow a remote attacker to make server-side requests to an attacker-controlled host, potentially ex…
CVE-2026-86158High· 7.7Missing authentication in the local .NET backend (Fiddler.WebUi) of Progress Software Fiddler Everywhere 8.0.2 allows a local unauthenticated attacker to mint OAuth tokens and read the machine-in-the-middle root certificate through an un…