CVE-2018-20406

7.5 HIGH 6% exploit odds Fix listed Memory safety Library

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of service disruption.
Exploit odds: 5.8% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2018-12-23 23:29 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-15 18:17 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 5.8% in the next 30 days (EPSS).
Severity: 7.5 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2018-12-23 23:29 UTC
Last modified: 2026-10-15 18:17 UTC
Exploit probability: 5.8% · EPSS, next 30 days
Weakness: CWE-190 · Integer overflow
Record status: Modified

Affected

Python < 3.7.1
Debian Linux 8.0
Fedoraproject Fedora 28
Fedoraproject Fedora 29
Fedoraproject Fedora 30

Attack profile CVSS 3.0 · 7.5

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Raw vector

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Is it in your code?

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Fix and advisories

References

NVD record · CVE.org record