CVE-2020-10933

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2020-05-04 · updated 2026-06-17
Weakness: CWE-908

Description

An issue was discovered in Ruby 2.5.x through 2.5.7, 2.6.x through 2.6.5, and 2.7.0. If a victim calls BasicSocket#read_nonblock(requested_size, buffer, exception: false), the method resizes the buffer to fit the requested size, but no data is copied. Thus, the buffer string provides the previous value of the heap. This may expose possibly sensitive data from the interpreter.

Affected products

Debian Linux: 10.0
Fedoraproject Fedora: 31
Ruby: from 2.5.0 through 2.5.7; from 2.6.0 through 2.6.5; 2.7.0

References

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/F4TNVTT66VPRMX5UZYSDGSVRXKKDDDU5/
https://security.netapp.com/advisory/ntap-20200625-0001/
https://www.debian.org/security/2020/dsa-4721
https://www.ruby-lang.org/en/news/2020/03/31/heap-exposure-in-socket-cve-2020-10933/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/F4TNVTT66VPRMX5UZYSDGSVRXKKDDDU5/
https://security.netapp.com/advisory/ntap-20200625-0001/
https://www.debian.org/security/2020/dsa-4721
https://www.ruby-lang.org/en/news/2020/03/31/heap-exposure-in-socket-cve-2020-10933/

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