# CVE-2016-9063: Python 3.5 and 1 other: An integer overflow during the parsing of XML using the Expat library.

CVE-2016-9063 is fixed in 3 products on 2 platforms, first by Python 3.6 3.6.2, released July 17, 2017. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2016-9063
- Priority: Urgent
- CVSS: 9.8
- EPSS: 0.0536
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 11, 2018
- Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2016-9063

## Description

An integer overflow during the parsing of XML using the Expat library. This vulnerability affects Firefox < 50.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Windows apps | Python 3.5 | 3.5.4 | [Python 3.5 3.5.4](https://patchblox.com/security/data/fix/windows-app/python.python.3.5-3.5.4.md) | Aug 7, 2017 |
| Windows apps | Python 3.6 | 3.6.2 | [Python 3.6 3.6.2](https://patchblox.com/security/data/fix/windows-app/python.python.3.6-3.6.2.md) | Jul 17, 2017 |
| Linux | expat sles 15.6 | 2.8.5-150400.3.40.1 | [SUSE-SU-2026:4623-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4623-1.md) | Nov 7, 2026 |

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Data as of 2026-11-07T06:34:28Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo