Vulnerability · Published Oct 26, 2026 · Assigned by GitHub_M
CVE-2026-116578Tornado: Open redirect in RedirectHandler via protocol-relative URLs
Low 2.1
In plain English
A low-severity open redirect in tornado from tornadoweb. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Tornado is a Python web framework and asynchronous networking library. Prior to 6.6, tornado.web.RedirectHandler URL templates can place regex-capture substitutions where crafted request paths change the redirect scheme or network location. Affected placements include substitutions at the start of a path, directly after a fixed host, or at the beginning of the template, including protocol-relative, absolute, backslash, encoded, host-extension, and user-info variants interpreted by browsers as attacker-controlled destinations. Static templates and substitutions after a fixed host followed by a slash are not affected. An attacker can use the resulting open redirect on the application's domain for phishing. This issue is fixed in version 6.6.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | python-tornado | no fix listed | DEBIAN-CVE-2026-116578 |
| Debian:13 | python-tornado | no fix listed | DEBIAN-CVE-2026-116578 |
| Debian:14 | python-tornado | no fix listed | DEBIAN-CVE-2026-116578 |
| PyPI | tornado | 6.6 | GHSA-pw9p-v7r6-gx4p |
| Ubuntu:24.04:LTS | python-tornado | no fix listed | UBUNTU-CVE-2026-116578 |
| Ubuntu:26.04:LTS | python-tornado | no fix listed | UBUNTU-CVE-2026-116578 |
| Ubuntu:26.10 | python-tornado | no fix listed | UBUNTU-CVE-2026-116578 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| tornadoweb | tornado | < 6.6 |
Weakness: CWE-601 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N
References
- https://github.com/tornadoweb/tornado/security/advisories/GHSA-pw9p-v7r6-gx4p x_refsource_CONFIRM
- https://github.com/tornadoweb/tornado/pull/3786 x_refsource_MISC
- https://github.com/tornadoweb/tornado/commit/940ea725bdd9bc68231d68a105eef17ea6e11233 x_refsource_MISC
- https://github.com/tornadoweb/tornado/commit/cc75ab0eb3af459c714895a49f682ad354f50117 x_refsource_MISC
- https://github.com/tornadoweb/tornado/commit/ccb6a2e5482f17997efd4a74b8200d5b4babc035 x_refsource_MISC
- https://github.com/tornadoweb/tornado/releases/tag/v6.6.0 x_refsource_MISC