CVE intelligence and bounded remediation

CVE-2020-25684 — A flaw was found in dnsmasq before version 2.83

Medium CVSS 4.3

A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq checks in the forward.c:reply_query() if the reply destination address/port is used by the pending forwarded queries. However, it does not use the address/port to retrieve the exact forwarded query, substantially reducing the number of attempts an attacker on the network would have to perform to forge a reply and get it accepted by dnsmasq. This issue contrasts with RFC5452, which specifies a query's attributes that all must be used to match a reply. This flaw allows an attacker to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25685 or CVE-2020-25686, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.

Severity
Medium
CVSS
4.3 (2.0)
Published
2021-01-20
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-358

Affected products

  • thekelleys / dnsmasq
  • fedoraproject / fedora / 32
  • fedoraproject / fedora / 33
  • debian / debian_linux / 9.0
  • debian / debian_linux / 10.0
  • arista / eos

Showing 6 representative product identities from 10 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

General vulnerability remediation

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Confirm the affected component, deployment paths, reachable interfaces, and enabled features from inventories and configuration, without probing production destructively.
  • Compare the advisory's affected conditions with the repository lockfiles, build manifests, artifacts, and runtime inventory.
  • Identify data sensitivity, trust boundaries, and privilege level for every confirmed affected deployment.

Remediate safely

  • Apply a vendor-supported fix or remove the affected component or feature; record the selected change and its source in the repository.
  • Update direct and transitive dependency locks, generated artifacts, deployment manifests, and asset inventories together.
  • Add a regression test for the documented unsafe condition using inert inputs and preserve rollback instructions.

Authoritative sources

Complete CVE record and remediation plan

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