What’s Vulnerable › Vulnerabilities

CVE-2018-20406

• Severity: high (CVSS 7.5 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 5.8% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2018-12-23 · updated 2026-10-15
• Weakness: CWE-190

Description

Modules/_pickle.c in Python before 3.7.1 has an integer overflow via a large LONG_BINPUT value that is mishandled during a "resize to twice the size" attempt. This issue might cause memory exhaustion, but is only relevant if the pickle format is used for serializing tens or hundreds of gigabytes of data. This issue is fixed in: v3.4.10, v3.4.10rc1; v3.5.10, v3.5.10rc1, v3.5.7, v3.5.7rc1, v3.5.8, v3.5.8rc1, v3.5.8rc2, v3.5.9; v3.6.10, v3.6.10rc1, v3.6.11, v3.6.11rc1, v3.6.12, v3.6.7, v3.6.7rc1, v3.6.7rc2, v3.6.8, v3.6.8rc1, v3.6.9, v3.6.9rc1; v3.7.1, v3.7.1rc1, v3.7.1rc2, v3.7.2, v3.7.2rc1, v3.7.3, v3.7.3rc1, v3.7.4, v3.7.4rc1, v3.7.4rc2, v3.7.5, v3.7.5rc1, v3.7.6, v3.7.6rc1, v3.7.7, v3.7.7rc1, v3.7.8, v3.7.8rc1, v3.7.9.

Affected products

• Debian Linux: 8.0
• Fedoraproject Fedora: 28, 29, 30
• Python: from 3.4.0 before 3.7.1 — fixed in 3.7.1

How to fix

Upgrade to a fixed version: Python 3.7.1. Check the vendor advisory for mitigations.

References

• http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00040.html
• https://access.redhat.com/errata/RHSA-2019:3725
• https://bugs.python.org/issue34656
• https://github.com/python/cpython/commit/a4ae828ee416a66d8c7bf5ee71d653c2cc6a26dd
• https://lists.debian.org/debian-lts-announce/2019/02/msg00011.html
• https://lists.debian.org/debian-lts-announce/2020/07/msg00011.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/46PVWY5LFP4BRPG3BVQ5QEEFYBVEXHCK/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AEZ5IQT7OF7Q2NCGIVABOWYGKO7YU3NJ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/D3LXPABKVLFYUHRYJPM3CSS5MS6FXKS7/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ICBEGRHIPHWPG2VGYS6R4EVKVUUF4AQW/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JSKPGPZQNTAULHW4UH63KGOOUIDE4RRB/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TR6GCO3WTV4D5L23WTCBF275VE6BVNI3/

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