# CVE-2026-103262: python3-tornado: Tornado versions before 6.5.9 contain an unbounded memory accumulation vulnerability in CurlAsyncHTTPClient that allo...

CVE-2026-103262 is fixed in 9 products on 1 platform, first by python3-tornado 6.5.4-0.1ubuntu0.2, released October 1, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-103262
- Priority: High
- CVSS: 7.5 (Medium)
- EPSS: 0.0063
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 1, 2026

## Description

Tornado versions before 6.5.9 contain an unbounded memory accumulation vulnerability in CurlAsyncHTTPClient that allows remote attackers to cause denial of service by sending a compressed response. Attackers can send a gzip-encoded decompression bomb that accumulates in memory without size limits, causing the application process to be killed by out-of-memory conditions.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | python-tornado RHEL 10 | 6.5.10-0.el10_0.1 | [RHSA-2026:91583](https://patchblox.com/security/data/fix/linux/rhsa-2026-91583.md) | Oct 13, 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 rocky 10 | 0:6.5.10-1.el10_2.1 | [RLSA-2026:82041](https://patchblox.com/security/data/fix/linux/rlsa-2026-82041.md) | Nov 7, 2026 |
| Linux | python-tornado rocky 9 | 0:6.5.10-1.el9_8.1 | [RLSA-2026:82040](https://patchblox.com/security/data/fix/linux/rlsa-2026-82040.md) | Nov 7, 2026 |
| Linux | python-tornado-debugsource amzn 2023 | 6.1.0-2.amzn2023.0.12 | [ALAS2023-2026-3292](https://patchblox.com/security/data/fix/linux/alas2023-2026-3292.md) | Nov 7, 2026 |
| Linux | python-tornado-doc amzn 2023 | 6.1.0-2.amzn2023.0.12 | [ALAS2023-2026-3292](https://patchblox.com/security/data/fix/linux/alas2023-2026-3292.md) | Nov 7, 2026 |
| Linux | python3-tornado RHEL 9 | 0:6.5.10-1.el9_8.1 | [RHSA-2026:82040](https://patchblox.com/security/data/fix/linux/rhsa-2026-82040.md) | Oct 13, 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 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 | 6.5.10-1.el10_2.1 | [ALSA-2026:82041](https://patchblox.com/security/data/fix/linux/alsa-2026-82041.md) | Nov 7, 2026 |
| Linux | python3-tornado almalinux 9 | 6.5.10-1.el9_8.1 | [ALSA-2026:82040](https://patchblox.com/security/data/fix/linux/alsa-2026-82040.md) | Nov 7, 2026 |
| Linux | python3-tornado amzn 2023 | 6.1.0-2.amzn2023.0.12 | [ALAS2023-2026-3292](https://patchblox.com/security/data/fix/linux/alas2023-2026-3292.md) | Nov 7, 2026 |
| Linux | python3-tornado ol 10 | 0:6.5.10-1.el10_2.1 | [ELSA-2026-82041](https://patchblox.com/security/data/fix/linux/elsa-2026-82041.md) | Nov 7, 2026 |
| Linux | python3-tornado ol 9 | 0:6.5.10-1.el9_8.1 | [ELSA-2026-82040](https://patchblox.com/security/data/fix/linux/elsa-2026-82040.md) | Nov 7, 2026 |
| Linux | python3-tornado-debuginfo amzn 2023 | 6.1.0-2.amzn2023.0.12 | [ALAS2023-2026-3292](https://patchblox.com/security/data/fix/linux/alas2023-2026-3292.md) | Nov 7, 2026 |
| Linux | python3.13-tornado amzn 2023 | 6.4.2-1.amzn2023.0.7 | [ALAS2023-2026-3293](https://patchblox.com/security/data/fix/linux/alas2023-2026-3293.md) | Nov 7, 2026 |
| Linux | python3.13-tornado-debuginfo amzn 2023 | 6.4.2-1.amzn2023.0.7 | [ALAS2023-2026-3293](https://patchblox.com/security/data/fix/linux/alas2023-2026-3293.md) | Nov 7, 2026 |
| Linux | python3.13-tornado-debugsource amzn 2023 | 6.4.2-1.amzn2023.0.7 | [ALAS2023-2026-3293](https://patchblox.com/security/data/fix/linux/alas2023-2026-3293.md) | Nov 7, 2026 |
| Linux | python3.13-tornado-doc amzn 2023 | 6.4.2-1.amzn2023.0.7 | [ALAS2023-2026-3293](https://patchblox.com/security/data/fix/linux/alas2023-2026-3293.md) | Nov 7, 2026 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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