Vulnerability Monitor

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CVE-2020-25686

A flaw was found in dnsmasq before version 2.83. When receiving a query, dnsmasq does not check for an existing pending request for the same name and forwards a new request. By default, a maximum of 150 pending queries can be sent to upstream servers, so there can be at most 150 queries for the same name. This flaw allows an off-path attacker on the network to substantially reduce the number of attempts that it would have to perform to forge a reply and have it accepted by dnsmasq. This issue is mentioned in the "Birthday Attacks" section of RFC5452. If chained with CVE-2020-25684, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.

Published

2021-01-20T17:15:13.000

Last Modified

2025-11-04T20:15:57.490

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 3.7 (LOW)

CVSSv2 Vector

AV:N/AC:M/Au:N/C:N/I:P/A:N

  • Access Vector: NETWORK
  • Access Complexity: MEDIUM
  • Authentication: NONE
  • Confidentiality Impact: NONE
  • Integrity Impact: PARTIAL
  • Availability Impact: NONE
Exploitability Score

8.6

Impact Score

2.9

Weaknesses
  • Type: Secondary
    CWE-358
  • Type: Secondary
    CWE-290
Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Application thekelleys dnsmasq < 2.83 Yes
Operating System fedoraproject fedora 32 Yes
Operating System fedoraproject fedora 33 Yes
Operating System debian debian_linux 10.0 Yes
Operating System arista eos < 4.21.14m Yes
Operating System arista eos < 4.22.9m Yes
Operating System arista eos < 4.23.7m Yes
Operating System arista eos < 4.24.5m Yes
Operating System arista eos < 4.25.2f Yes
References