CVE-2020-25681: A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in the way RRSets are sorted before validating with DNSSEC data. An attacker on the network who can forge DNS replies such as that they are accepted as valid could use this flaw to cause a buffer overflow with arbitrary data in a heap memory segment possibly executing code on the machine. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Overview

Severity

High (CVSS 8.1)

CVSS Vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Status

Not Exploited

Patch Tuesday

2021-Jan

Released

2021-01-29

EPSS Score

45.36% (percentile: 97.6%)

FAQ

Is Azure Linux the only Microsoft product that includes this open-source library and is therefore potentially affected by this vulnerability? One of the main benefits to our customers who choose to use the Azure Linux distro is the commitment to keep it up to date with the most recent and most secure versions of the open source libraries with which the distro is composed. Microsoft is committed to transparency in this work which is why we began publishing CSAF/VEX in October 2025. See this blog post for more information. If impact to additional products is identified, we will update the CVE to reflect this.

Detection & Weaponization (1 sources)

Maturity: Exploit

• GitHub PoC: 2 repositories

Affected Products (1)

Other

• 19065-16820

Revision History

• 2021-01-29: Information published.