UBUNTU-CVE-2021-3448

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    UBUNTU-CVE-2021-3448

    Published: 8 Apr 2021Last Modified: 26 May 2026
    Upstream:
    CVE-2021-3448

    Summary:

    Details: A flaw was found in dnsmasq in versions before 2.85. When configured to use a specific server for a given network interface, dnsmasq uses a fixed port while forwarding queries. An attacker on the network, able to find the outgoing port used by dnsmasq, only needs to guess the random transmission ID to forge a reply and get it accepted by dnsmasq. This flaw makes a DNS Cache Poisoning attack much easier. The highest threat from this vulnerability is to data integrity.

    References: https://ubuntu.com/security/CVE-2021-3448, https://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2021q1/014835.html, https://ubuntu.com/security/notices/USN-4976-1, https://ubuntu.com/security/notices/USN-4976-2, https://www.cve.org/CVERecord?id=CVE-2021-3448

    Affected packages

    Package

    Name: dnsmasq

    Purl: pkg:deb/ubuntu/dnsmasq?arch=source&distro=esm-infra-legacy%2Ftrusty

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    2.66-4ubuntu1

    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-2021-3448 | CVE-DB