Description
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
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| tornadoweb | tornado | < 6.5.7 | 6.5.7 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | python-tornado | No fix yet | — |
| Debian 13 | python-tornado | No fix yet | — |
| Debian 12 | python-tornado | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | python-tornado | 6.5.5-5ubuntu1.1 | USN-8952-1 |
| Ubuntu 26.04 LTS | python-tornado | 6.5.4-0.1ubuntu0.2 | USN-8952-1 |
| Ubuntu 24.04 LTS | python-tornado | 6.4.0-1ubuntu0.6 | USN-8952-1 |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 22.04 LTS | python-tornado | 6.1.0-3ubuntu0.1~esm6 | USN-8952-1 |
| Ubuntu Pro 20.04 LTS | python-tornado | 6.0.3+really5.1.1-3ubuntu0.1~esm7 | USN-8952-1 |
| Ubuntu Pro 18.04 LTS | python-tornado | 4.5.3-1ubuntu0.2+esm4 | USN-8952-1 |
| Ubuntu Pro 16.04 LTS | python-tornado | 4.2.1-1ubuntu3.1+esm4 | USN-8952-1 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | python-tornado | No fix yet | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | tornado | < 6.5.7 | 6.5.7 | GHSA-pw6j-qg29-8w7f |
Advisories 1
- USN-8952-1 python-tornado vulnerabilities Ubuntu Security Notices (USN) · Nov 6, 2026
References
- GitHub Security Advisory (GHSA-pw6j-qg29-8w7f) vendor-advisory
- VulnCheck Advisory: Tornado before 6.5.7 Credential Leak via Handle Reuse third-party-advisory