CVE-2018-8778

Severity: high (CVSS 7.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 7.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-04-03 · updated 2026-06-17
Weakness: CWE-134

Description

In Ruby before 2.2.10, 2.3.x before 2.3.7, 2.4.x before 2.4.4, 2.5.x before 2.5.1, and 2.6.0-preview1, an attacker controlling the unpacking format (similar to format string vulnerabilities) can trigger a buffer under-read in the String#unpack method, resulting in a massive and controlled information disclosure.

Affected products

Canonical Ubuntu Linux: 14.04, 16.04, 17.10
Debian Linux: 7.0, 8.0, 9.0
Red Hat Enterprise Linux: 6.0, 7.0, 7.4, 7.5, 7.6
Ruby: from 2.2.0 before 2.2.10; from 2.3.0 before 2.3.7; from 2.4.0 before 2.4.4; from 2.5.0 before 2.5.1; 2.6.0-preview1 — fixed in 2.2.10, 2.3.7, 2.4.4, 2.5.1

How to fix

Upgrade to a fixed version: Ruby 2.2.10, 2.3.7, 2.4.4, 2.5.1. Check the vendor advisory for mitigations.

References

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