CVE-2026-91992

Tornado before 6.5.7 contains a credential leak vulnerability in CurlAsyncHTTPClient where pycurl handles are reused across requests without proper state clearing. Attackers can obtain sensitive credentials by issuing requests through the same client instance, allowing TLS certificates or proxy authentication to persist across unintended requests.

  • Published Sep 15, 2026
  • CVSS 8.2 high
  • 0.3% chance of exploitation in the next 30 days (EPSS)
  • A fix is available

Affected software

CVE-2026-91992 at the National Vulnerability Database