# CVE-2026-91990: python3-tornado: Tornado before 6.5.8 contains a memory amplification vulnerability in parse_multipart_form_data that splits multipart... CVE-2026-91990 is fixed in 10 products on 1 platform, first by ALSA-2026:67147, released September 14, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-91990 - Priority: High - CVSS: 7.5 (Medium) - EPSS: 0.0042 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Sep 14, 2026 ## Description Tornado before 6.5.8 contains a memory amplification vulnerability in parse_multipart_form_data that splits multipart data before validating the max_parts limit. Attackers can send crafted multipart requests with many parts to create large transient lists, exhausting server memory and causing denial of service. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | python-tornado RHEL 10 | 6.5.8-0.el10_0.1 | [RHSA-2026:80741](https://patchblox.com/security/data/fix/linux/rhsa-2026-80741.md) | Sep 14, 2026 | | Linux | python-tornado Ubuntu 18.04.6 LTS (bionic) | 4.5.3-1ubuntu0.2+esm4 | [python-tornado 4.5.3-1ubuntu0.2+esm4](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python-tornado-4.5.3-1ubuntu0.2-esm4.md) | Oct 24, 2026 | | Linux | python-tornado sles 15.6 | 4.5.3-150000.3.31.1 | [SUSE-SU-2026:4404-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4404-1.md) | Sep 30, 2026 | | Linux | python-tornado sles 15.7 | 4.5.3-150000.3.31.1 | [SUSE-SU-2026:4404-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4404-1.md) | Sep 30, 2026 | | Linux | python-tornado-debugsource amzn 2023 | 6.1.0-2.amzn2023.0.11 | [ALAS2023-2026-3177](https://patchblox.com/security/data/fix/linux/alas2023-2026-3177.md) | Nov 7, 2026 | | Linux | python-tornado-doc amzn 2023 | 6.1.0-2.amzn2023.0.11 | [ALAS2023-2026-3177](https://patchblox.com/security/data/fix/linux/alas2023-2026-3177.md) | Nov 7, 2026 | | Linux | python-tornado6 opensuse-leap 16.0 | 6.5-160000.7.1 | [OPENSUSE-SU-2026:22059-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22059-1.md) | Nov 7, 2026 | | Linux | python-tornado6 sles 15.6 | 6.3.2-150400.9.27.1 | [SUSE-SU-2026:4403-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4403-1.md) | Sep 30, 2026 | | Linux | python-tornado6 sles 15.7 | 6.3.2-150400.9.27.1 | [SUSE-SU-2026:4403-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4403-1.md) | Sep 30, 2026 | | Linux | python-tornado6 sles 16.0 | 6.5-160000.7.1 | [SUSE-SU-2026:24207-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24207-1.md) | Nov 7, 2026 | | Linux | python3-tornado RHEL 9 | 0:6.5.8-0.el9_8.1 | [RHSA-2026:67146](https://patchblox.com/security/data/fix/linux/rhsa-2026-67146.md) | Sep 19, 2026 | | Linux | python3-tornado Ubuntu 18.04.6 LTS (bionic) | 4.5.3-1ubuntu0.2+esm4 | [python3-tornado 4.5.3-1ubuntu0.2+esm4](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python3-tornado-4.5.3-1ubuntu0.2-esm4.md) | Oct 24, 2026 | | Linux | python3-tornado Ubuntu 22.04.1 LTS (jammy) | 6.1.0-3ubuntu0.1~esm6 | [python3-tornado 6.1.0-3ubuntu0.1~esm6](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-python3-tornado-6.1.0-3ubuntu0.1-esm6.md) | Oct 24, 2026 | | Linux | python3-tornado Ubuntu 24.04.5 LTS (noble) | 6.4.0-1ubuntu0.6 | [python3-tornado 6.4.0-1ubuntu0.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-python3-tornado-6.4.0-1ubuntu0.6.md) | Oct 24, 2026 | | Linux | python3-tornado Ubuntu 26.04.1 LTS (resolute) | 6.5.4-0.1ubuntu0.2 | [python3-tornado 6.5.4-0.1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-python3-tornado-6.5.4-0.1ubuntu0.2.md) | Oct 1, 2026 | | Linux | python3-tornado almalinux 10 | 6.5.8-0.el10_2.1 | [ALSA-2026:67147](https://patchblox.com/security/data/fix/linux/alsa-2026-67147.md) | Sep 14, 2026 | | Linux | python3-tornado almalinux 9 | 6.5.8-0.el9_8.1 | [ALSA-2026:67146](https://patchblox.com/security/data/fix/linux/alsa-2026-67146.md) | Sep 14, 2026 | | Linux | python3-tornado amzn 2023 | 6.1.0-2.amzn2023.0.11 | [ALAS2023-2026-3177](https://patchblox.com/security/data/fix/linux/alas2023-2026-3177.md) | Nov 7, 2026 | | Linux | python3-tornado-debuginfo amzn 2023 | 6.1.0-2.amzn2023.0.11 | [ALAS2023-2026-3177](https://patchblox.com/security/data/fix/linux/alas2023-2026-3177.md) | Nov 7, 2026 | | Linux | python3.13-tornado amzn 2023 | 6.4.2-1.amzn2023.0.6 | [ALAS2023-2026-3176](https://patchblox.com/security/data/fix/linux/alas2023-2026-3176.md) | Nov 7, 2026 | | Linux | python3.13-tornado-debuginfo amzn 2023 | 6.4.2-1.amzn2023.0.6 | [ALAS2023-2026-3176](https://patchblox.com/security/data/fix/linux/alas2023-2026-3176.md) | Nov 7, 2026 | | Linux | python3.13-tornado-debugsource amzn 2023 | 6.4.2-1.amzn2023.0.6 | [ALAS2023-2026-3176](https://patchblox.com/security/data/fix/linux/alas2023-2026-3176.md) | Nov 7, 2026 | | Linux | python3.13-tornado-doc amzn 2023 | 6.4.2-1.amzn2023.0.6 | [ALAS2023-2026-3176](https://patchblox.com/security/data/fix/linux/alas2023-2026-3176.md) | Nov 7, 2026 | --- Data as of 2026-11-08T00:53:09Z UTC. 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