CVE-2020-10933

Name: CVE-2020-10933
Creator: NVD / NIST
Published: 2020-05-04T15:15:13.963+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.3/10EPSS 2.56%

Last modified Jun 17, 2026

CVE-2020-10933 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. 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. EPSS estimates a 2.56% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

5.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS Probability

2.56%

83.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-908

Affected Software

Vendor	Product	Versions
Ruby-Lang	Ruby	>= 2.5.0, <= 2.5.7
Ruby-Lang	Ruby	>= 2.6.0, <= 2.6.5
Ruby-Lang	Ruby	2.7.0
Fedoraproject	Fedora	31
Debian	Debian Linux	10.0

References

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

Timeline

Published: May 4, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-10933?

How severe is CVE-2020-10933?

CVE-2020-10933 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 2.56% probability of exploitation in the next 30 days.

How do I fix CVE-2020-10933?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-10933?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST