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MEDIUM

CVE-2020-10933

CVSS v3

5.3

MEDIUM

EPSS Score

2.5 %

exploit probability, as of 2026-10-19

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • rubyBitnamifrom 2.5.0 · fixed in 2.5.8and 1 other package
  • rubygem-abrtAlmaLinux:8all versions · fixed in 0.3.0-4.module_el8.5.0+2623+08a8ba32and 1 other package
  • rubygem-bsonAlmaLinux:8all versions · fixed in 4.5.0-1.module_el8.5.0+250+ba22dbf7
  • rubygem-bson-docAlmaLinux:8all versions · fixed in 4.5.0-1.module_el8.5.0+2623+08a8ba32
  • rubygem-mongoAlmaLinux:8all versions · fixed in 2.8.0-1.module_el8.5.0+2623+08a8ba32and 1 other package
  • rubygem-mysql2AlmaLinux:8all versions · fixed in 0.5.2-1.module_el8.5.0+2623+08a8ba32and 1 other package
  • rubygem-pgAlmaLinux:8all versions · fixed in 1.1.4-1.module_el8.5.0+2623+08a8ba32
  • rubygem-pg-docAlmaLinux:8all versions · fixed in 1.1.4-1.module_el8.5.0+250+ba22dbf7

Vendor advisories

  • CVE-2020-10933 Red Hat Product Security767 products fixed

    ruby: BasicSocket#read_nonblock method leads to information disclosure

  • RHSA-2022:0582 Red Hat Product Security142 products fixed

    Red Hat Security Advisory: ruby:2.6 security update

  • RHSA-2022:0581 Red Hat Product Security92 products fixed

    Red Hat Security Advisory: ruby:2.6 security update

  • RHSA-2021:2587 Red Hat Product Security144 products fixed

    Red Hat Security Advisory: ruby:2.5 security, bug fix, and enhancement update

  • RHSA-2021:2588 Red Hat Product Security142 products fixed

    Red Hat Security Advisory: ruby:2.6 security, bug fix, and enhancement update

  • RHSA-2021:2230 Red Hat Product Security105 products fixed

    Red Hat Security Advisory: rh-ruby26-ruby security, bug fix, and enhancement update

1 more advisory

Full record on NVD

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.

Technical details

Published
2020-05-04

Frequently asked questions

What is CVE-2020-10933?

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.

Is CVE-2020-10933 actively exploited?

Active exploitation of CVE-2020-10933 has not been confirmed. Its EPSS score was 2.5% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-10933?

CVE-2020-10933 has a CVSS v3 base score of 5.3 (MEDIUM severity).

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