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Gentoo Linux Security Advisory                           GLSA 202105-20
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                                            https://security.gentoo.org/
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  Severity: Low
     Title: Dnsmasq: DNS cache poisoning
      Date: May 26, 2021
      Bugs: #782130
        ID: 202105-20

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Synopsis
========

Use of insufficient randomness in Dnsmasq might lead to DNS Cache
Poisoning.

Background
==========

Dnsmasq is a lightweight and easily-configurable DNS forwarder and DHCP
server.

Affected packages
=================

     -------------------------------------------------------------------
      Package              /     Vulnerable     /            Unaffected
     -------------------------------------------------------------------
   1  net-dns/dnsmasq               < 2.85                     >= 2.85

Description
===========

It was discovered that Dnsmasq, when configured with
--server=
@ or similar (e.g. through dbus), configured a fixed UDP port for all outgoing queries to the specified upstream DNS server. Impact ====== An attacker, by sending malicious crafted DNS responses, could perform a DNS Cache Poisoning attack. Workaround ========== There is no known workaround at this time. Resolution ========== All Dnsmasq users should upgrade to the latest version: # emerge --sync # emerge --ask --oneshot --verbose ">=net-dns/dnsmasq-2.85" References ========== [ 1 ] CVE-2021-3448 https://nvd.nist.gov/vuln/detail/CVE-2021-3448 Availability ============ This GLSA and any updates to it are available for viewing at the Gentoo Security Website: https://security.gentoo.org/glsa/202105-20 Concerns? ========= Security is a primary focus of Gentoo Linux and ensuring the confidentiality and security of our users' machines is of utmost importance to us. Any security concerns should be addressed to [email protected] or alternatively, you may file a bug at https://bugs.gentoo.org. License ======= Copyright 2021 Gentoo Foundation, Inc; referenced text belongs to its owner(s). The contents of this document are licensed under the Creative Commons - Attribution / Share Alike license. https://creativecommons.org/licenses/by-sa/2.5