Description
Tornado before 6.4.1 contains a CRLF injection vulnerability in CurlAsyncHTTPClient that fails to reject carriage return and line feed characters in request headers. Attackers can inject CRLF sequences into header values to inject arbitrary headers or construct entirely new HTTP requests.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| tornadoweb | tornado | < 6.4.1 | 6.4.1 |
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 | 6.4.1-1 | — |
| Debian 13 | python-tornado | 6.4.1-1 | — |
| Debian 12 | python-tornado | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | python-tornado | No fix yet | — |
| Ubuntu 26.04 LTS | python-tornado | No fix yet | — |
| Ubuntu 24.04 LTS | python-tornado | No fix yet | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 22.04 LTS | python-tornado | No fix yet | — |
| Ubuntu Pro 20.04 LTS | python-tornado | No fix yet | — |
| Ubuntu Pro 18.04 LTS | python-tornado | No fix yet | — |
| Ubuntu Pro 16.04 LTS | python-tornado | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | python-tornado | 4.5.3-150000.3.31.1 | SUSE-SU-2026:4404-1 |
| SLES 15 SP6 | python-tornado | 4.5.3-150000.3.31.1 | SUSE-SU-2026:4404-1 |
| SLES 15 SP6 | python-tornado6 | 6.3.2-150400.9.27.1 | SUSE-SU-2026:4403-1 |
| SLES 15 SP5 | python-tornado | 4.5.3-150000.3.31.1 | SUSE-SU-2026:4404-1 |
| SLES 15 SP5 | python-tornado6 | 6.3.2-150400.9.27.1 | SUSE-SU-2026:4403-1 |
| SLES 15 SP4 | python-tornado | 4.5.3-150000.3.31.1 | SUSE-SU-2026:4404-1 |
| SLES 15 SP4 | python-tornado6 | 6.3.2-150400.9.27.1 | SUSE-SU-2026:4403-1 |
| SLES 3 | python-tornado6 | 6.3.2-150400.9.27.1 | SUSE-SU-2026:4403-1 |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 SP6 | python-tornado | 4.5.3-150000.3.31.1 | SUSE-SU-2026:4404-1 |
| SLES for SAP 15 SP6 | python-tornado6 | 6.3.2-150400.9.27.1 | SUSE-SU-2026:4403-1 |
| SLES for SAP 15 SP5 | python-tornado | 4.5.3-150000.3.31.1 | SUSE-SU-2026:4404-1 |
| SLES for SAP 15 SP5 | python-tornado6 | 6.3.2-150400.9.27.1 | SUSE-SU-2026:4403-1 |
| SLES for SAP 15 SP4 | python-tornado | 4.5.3-150000.3.31.1 | SUSE-SU-2026:4404-1 |
| SLES for SAP 15 SP4 | python-tornado6 | 6.3.2-150400.9.27.1 | SUSE-SU-2026:4403-1 |
| SLE Micro 5.5 | python-tornado | 4.5.3-150000.3.31.1 | SUSE-SU-2026:4404-1 |
| SLE Micro 5.4 | python-tornado | 4.5.3-150000.3.31.1 | SUSE-SU-2026:4404-1 |
| SLE Micro 5.3 | python-tornado | 4.5.3-150000.3.31.1 | SUSE-SU-2026:4404-1 |
| SLE HPC 15 SP5 | python-tornado | 4.5.3-150000.3.31.1 | SUSE-SU-2026:4404-1 |
| SLE HPC 15 SP5 | python-tornado6 | 6.3.2-150400.9.27.1 | SUSE-SU-2026:4403-1 |
| SLE HPC 15 SP4 | python-tornado | 4.5.3-150000.3.31.1 | SUSE-SU-2026:4404-1 |
| SLE HPC 15 SP4 | python-tornado6 | 6.3.2-150400.9.27.1 | SUSE-SU-2026:4403-1 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | python-tornado | No fix yet | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | tornado | < 6.4.1 | 6.4.1 | GHSA-w235-7p84-xx57 |
Advisories 2
- SUSE-SU-2026:4403-1 Security update for python-tornado6 SUSE / openSUSE Security Updates · Oct 1, 2026
- SUSE-SU-2026:4404-1 Security update for python-tornado SUSE / openSUSE Security Updates · Oct 1, 2026
References
- GitHub Security Advisory (GHSA-w235-7p84-xx57) vendor-advisory
- VulnCheck Advisory: Tornado before 6.4.1 CRLF Injection via CurlAsyncHTTPClient third-party-advisory