CVE-2026-77804
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.
- CVSS 3.1
- 6.6
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N - EPSS
- 0.07% chance of exploitation in the next 30 days; higher than 0% of CVEs (scores of 2026-10-25)
- CWE
- CWE-367
- Published
- Modified
- Record from
- the NVD, synced