CVE-2020-25682

What it is

A flaw was found in dnsmasq before 2.83. A buffer overflow vulnerability was discovered in the way dnsmasq extract names from DNS packets before validating them with DNSSEC data. An attacker on the network, who can create valid DNS replies, could use this flaw to cause an overflow with arbitrary data in a heap-allocated memory, possibly executing code on the machine. The flaw is in the rfc1035.c:extract_name() function, which writes data to the memory pointed by name assuming MAXDNAME*2 bytes are available in the buffer. However, in some code execution paths, it is possible extract_name() gets passed an offset from the base buffer, thus reducing, in practice, the number of available bytes that can be written in the buffer. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.

Exploit odds

75.1% chance of exploitation in the next 30 days (EPSS). Higher than most.

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2020-09-16 00:00 UTC ReservedThe CVE id was reserved by its CNA
2. 2021-01-20 17:15 UTC PublishedDisclosed publicly on CVE.org and NVD
3. 2026-06-17 03:07 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 75.1% in the next 30 days (EPSS).
• Severity: 8.1 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-01-20 17:15 UTC

Last modified

2026-06-17 03:07 UTC

Exploit probability

75.1% · EPSS, next 30 days

Weakness

CWE-122

Record status

Modified

Affected

• Thekelleys Dnsmasq < 2.83
• Fedoraproject Fedora 32
• Fedoraproject Fedora 33
• Debian Linux 9.0
• Debian Linux 10.0

Attack profile CVSS 3.1 · 8.1

Attack vector

Network

Complexity

High

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2020-25682.md and follow it. Check whether this project is affected by CVE-2020-25682. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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