# CVE-2026-35536: python3-tornado: In Tornado before 6.5.5, cookie attribute injection could occur because the domain, path, and samesite arguments to .... CVE-2026-35536 is fixed in 9 products on 1 platform, first by python3-tornado 6.5.4-0.1ubuntu0.1, released April 2, 2026. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2026-35536 - Priority: Routine - CVSS: 5.4 (Medium) - EPSS: 0.0025 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Apr 2, 2026 ## 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. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | python-tornado Debian 14 | 6.5.5-1 | [DEBIAN-CVE-2026-35536](https://patchblox.com/security/data/fix/linux/debian-cve-2026-35536.md) | Apr 3, 2026 | | Linux | python-tornado Fedora 43 | 6.5.7-1.fc43 | [FEDORA-2026-23656E6D2F](https://patchblox.com/security/data/fix/linux/fedora-2026-23656e6d2f.md) | Jul 3, 2026 | | Linux | python-tornado RHEL 10 | 6.4.2-1.el10_0.2 | [RHSA-2026:20577](https://patchblox.com/security/data/fix/linux/rhsa-2026-20577.md) | Apr 3, 2026 | | Linux | python-tornado Ubuntu 18.04.6 LTS (bionic) | 4.5.3-1ubuntu0.2+esm3 | [python-tornado 4.5.3-1ubuntu0.2+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python-tornado-4.5.3-1ubuntu0.2-esm3.md) | Apr 30, 2026 | | Linux | python-tornado rocky 10 | 0:6.5.5-1.el10_1.1 | [RLSA-2026:19034](https://patchblox.com/security/data/fix/linux/rlsa-2026-19034.md) | May 29, 2026 | | Linux | python-tornado rocky 9 | 0:6.5.5-1.el9_7.1 | [RLSA-2026:19189](https://patchblox.com/security/data/fix/linux/rlsa-2026-19189.md) | May 21, 2026 | | Linux | python-tornado-debugsource Fedora 43 | 6.5.7-1.fc43 | [FEDORA-2026-23656E6D2F](https://patchblox.com/security/data/fix/linux/fedora-2026-23656e6d2f.md) | Jul 3, 2026 | | Linux | python-tornado-debugsource amzn 2023 | 6.1.0-2.amzn2023.0.8 | [ALAS2023-2026-1587](https://patchblox.com/security/data/fix/linux/alas2023-2026-1587.md) | Apr 13, 2026 | | Linux | python-tornado-doc Fedora 43 | 6.5.7-1.fc43 | [FEDORA-2026-23656E6D2F](https://patchblox.com/security/data/fix/linux/fedora-2026-23656e6d2f.md) | Jul 3, 2026 | | Linux | python-tornado-doc amzn 2023 | 6.1.0-2.amzn2023.0.8 | [ALAS2023-2026-1587](https://patchblox.com/security/data/fix/linux/alas2023-2026-1587.md) | Apr 13, 2026 | | Linux | python3-tornado Fedora 43 | 6.5.7-1.fc43 | [FEDORA-2026-23656E6D2F](https://patchblox.com/security/data/fix/linux/fedora-2026-23656e6d2f.md) | Jul 3, 2026 | | Linux | python3-tornado RHEL 9 | 0:6.5.5-1.el9_8 | [RHSA-2026:19189](https://patchblox.com/security/data/fix/linux/rhsa-2026-19189.md) | May 15, 2026 | | Linux | python3-tornado Ubuntu 18.04.6 LTS (bionic) | 4.5.3-1ubuntu0.2+esm3 | [python3-tornado 4.5.3-1ubuntu0.2+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python3-tornado-4.5.3-1ubuntu0.2-esm3.md) | Apr 30, 2026 | | Linux | python3-tornado Ubuntu 22.04.1 LTS (jammy) | 6.1.0-3ubuntu0.1~esm5 | [python3-tornado 6.1.0-3ubuntu0.1~esm5](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-python3-tornado-6.1.0-3ubuntu0.1-esm5.md) | Apr 30, 2026 | | Linux | python3-tornado Ubuntu 24.04.5 LTS (noble) | 6.4.0-1ubuntu0.5 | [python3-tornado 6.4.0-1ubuntu0.5](https://patchblox.com/security/data/fix/linux/ubuntu-noble-python3-tornado-6.4.0-1ubuntu0.5.md) | Apr 30, 2026 | | Linux | python3-tornado Ubuntu 25.10 (questing) | 6.4.2-3ubuntu0.3 | [python3-tornado 6.4.2-3ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-questing-python3-tornado-6.4.2-3ubuntu0.3.md) | Apr 30, 2026 | | Linux | python3-tornado Ubuntu 26.04.1 LTS (resolute) | 6.5.4-0.1ubuntu0.1 | [python3-tornado 6.5.4-0.1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-python3-tornado-6.5.4-0.1ubuntu0.1.md) | Apr 2, 2026 | | Linux | python3-tornado almalinux 10 | 6.5.5-1.el10_2 | [ALSA-2026:19034](https://patchblox.com/security/data/fix/linux/alsa-2026-19034.md) | May 19, 2026 | | Linux | python3-tornado almalinux 9 | 6.5.5-1.el9_8 | [ALSA-2026:19189](https://patchblox.com/security/data/fix/linux/alsa-2026-19189.md) | May 19, 2026 | | Linux | python3-tornado amzn 2023 | 6.1.0-2.amzn2023.0.8 | [ALAS2023-2026-1587](https://patchblox.com/security/data/fix/linux/alas2023-2026-1587.md) | Apr 13, 2026 | | Linux | python3-tornado ol 10 | 0:6.5.5-1.el10_1.1 | [ELSA-2026-13641](https://patchblox.com/security/data/fix/linux/elsa-2026-13641.md) | May 5, 2026 | | Linux | python3-tornado ol 9 | 0:6.5.5-1.el9_7.1 | [ELSA-2026-13670](https://patchblox.com/security/data/fix/linux/elsa-2026-13670.md) | May 5, 2026 | | Linux | python3-tornado-debuginfo Fedora 43 | 6.5.7-1.fc43 | [FEDORA-2026-23656E6D2F](https://patchblox.com/security/data/fix/linux/fedora-2026-23656e6d2f.md) | Jul 3, 2026 | | Linux | python3-tornado-debuginfo amzn 2023 | 6.1.0-2.amzn2023.0.8 | [ALAS2023-2026-1587](https://patchblox.com/security/data/fix/linux/alas2023-2026-1587.md) | Apr 13, 2026 | | Linux | python3.13-tornado amzn 2023 | 6.4.2-1.amzn2023.0.3 | [ALAS2023-2026-1588](https://patchblox.com/security/data/fix/linux/alas2023-2026-1588.md) | Apr 27, 2026 | | Linux | python3.13-tornado-debuginfo amzn 2023 | 6.4.2-1.amzn2023.0.3 | [ALAS2023-2026-1588](https://patchblox.com/security/data/fix/linux/alas2023-2026-1588.md) | Apr 27, 2026 | | Linux | python3.13-tornado-debugsource amzn 2023 | 6.4.2-1.amzn2023.0.3 | [ALAS2023-2026-1588](https://patchblox.com/security/data/fix/linux/alas2023-2026-1588.md) | Apr 27, 2026 | | Linux | python3.13-tornado-doc amzn 2023 | 6.4.2-1.amzn2023.0.3 | [ALAS2023-2026-1588](https://patchblox.com/security/data/fix/linux/alas2023-2026-1588.md) | Apr 27, 2026 | --- Data as of 2026-11-08T06:59:42Z UTC. 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