Vulnerability · Published Apr 3, 2026 · Assigned by mitre
CVE-2026-35536
High 7.2
In plain English
A high-severity security flaw 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 0.2% (higher than 16% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)7.2High
Exploit odds (30 days)0.2%top 84.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
In Tornado before 6.5.5, cookie attribute injection could occur because the domain, path, and samesite arguments to .RequestHandler.set_cookie were not checked for crafted characters.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | python3-tornado | 6.5.5-1.el10_2 | ALSA-2026:19034 |
| AlmaLinux:10 | python3-tornado | 6.5.5-1.el10_1.1 | ALSA-2026:13641 |
| AlmaLinux:9 | python3-tornado | 6.5.5-1.el9_8 | ALSA-2026:19189 |
| AlmaLinux:9 | python3-tornado | 6.5.5-1.el9_7.1 | ALSA-2026:13670 |
| Debian:12 | python-tornado | no fix listed | DEBIAN-CVE-2026-35536 |
| Debian:13 | python-tornado | no fix listed | DEBIAN-CVE-2026-35536 |
| Debian:14 | python-tornado | 6.5.5-1 | DEBIAN-CVE-2026-35536 |
| PyPI | tornado | 6.5.5 | GHSA-78cv-mqj4-43f7 |
| PyPI | tornado | 6.5.5 | GHSA-fqwm-6jpj-5wxc |
| PyPI | tornado | 6.5.5 | PYSEC-2026-2287 |
| Rocky Linux:10 | python-tornado | 0:6.5.5-1.el10_1.1 | RLSA-2026:13641 |
| Rocky Linux:10 | python-tornado | 0:6.5.5-1.el10_1.1 | RLSA-2026:19034 |
| Rocky Linux:9 | python-tornado | 0:6.5.5-1.el9_7.1 | RLSA-2026:13670 |
| Rocky Linux:9 | python-tornado | 0:6.5.5-1.el9_7.1 | RLSA-2026:19189 |
| Ubuntu:24.04:LTS | python-tornado | 6.4.0-1ubuntu0.5 | UBUNTU-CVE-2026-35536 |
| Ubuntu:25.10 | python-tornado | 6.4.2-3ubuntu0.3 | UBUNTU-CVE-2026-35536 |
| Ubuntu:26.04:LTS | python-tornado | 6.5.4-0.1ubuntu0.1 | UBUNTU-CVE-2026-35536 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| tornadoweb | Tornado | 0 – before 6.5.5 |
Weakness: CWE-159 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N