CVE-2026-91992: Tornadoweb Tornado

Medium severity, CVSS 5.9. EPSS: 0.3% chance of exploitation in the next 30 days.

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.

Affected products

• Tornadoweb Tornado: before 6.5.7 (fixed in 6.5.7)

Published 2026-09-15. Last modified 2026-09-17.