UBUNTU-CVE-2021-31810

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    UBUNTU-CVE-2021-31810

    Published: 13 Jul 2021Last Modified: 22 Apr 2026
    Upstream:
    CVE-2021-31810
    Aliases:
    USN-5020-1

    Summary:

    Details: An issue was discovered in Ruby through 2.6.7, 2.7.x through 2.7.3, and 3.x through 3.0.1. A malicious FTP server can use the PASV response to trick Net::FTP into connecting back to a given IP address and port. This potentially makes curl extract information about services that are otherwise private and not disclosed (e.g., the attacker can conduct port scans and service banner extractions).

    References: https://ubuntu.com/security/CVE-2021-31810, https://www.ruby-lang.org/en/news/2021/07/07/trusting-pasv-responses-in-net-ftp/, https://github.com/ruby/ruby/commit/3ca1399150ed4eacfd2fe1ee251b966f8d1ee469, https://hackerone.com/reports/1145454, https://ubuntu.com/security/notices/USN-5020-1, https://www.cve.org/CVERecord?id=CVE-2021-31810

    Affected packages

    Package

    Name: ruby2.3

    Purl: pkg:deb/ubuntu/[email protected]~ubuntu16.04.16+esm1?arch=source&distro=esm-infra/xenial

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -2.3.1-2~ubuntu16.04.16+esm1

    Affected versions

    2.3.0-1
    2.3.0-2
    2.3.0-4ubuntu2
    2.3.0-4ubuntu3
    2.3.0-5ubuntu1
    2.3.1-2~16.04
    2.3.1-2~16.04.2
    2.3.1-2~16.04.4
    2.3.1-2~16.04.5
    2.3.1-2~16.04.6
    2.3.1-2~16.04.7
    2.3.1-2~16.04.9
    2.3.1-2~16.04.10
    2.3.1-2~16.04.11
    2.3.1-2~16.04.12
    2.3.1-2~ubuntu16.04.13
    2.3.1-2~ubuntu16.04.14
    2.3.1-2~ubuntu16.04.15
    2.3.1-2~ubuntu16.04.16

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    UBUNTU-CVE-2021-31810 | CVE-DB