# CVE-2020-25684: Other in dnsmasq

> An attacker can forge DNS replies to poison the cache due to insufficient validation of forwarded query attributes, compromising data integrity.

- **Severity:** Low 3.7 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 20 Jan 2021
- **Updated:** 4 Nov 2025
- **Also known as:** ALPINE-CVE-2020-25684, CLEANSTART-2026-PQ68728, DEBIAN-CVE-2020-25684, GHSA-xqvc-9mc9-4fgx, UBUNTU-CVE-2020-25684

## What is CVE-2020-25684?

CVE-2020-25684 is a low-severity vulnerability in Debian Debian Linux, published on 20 Jan 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-358 (Improperly Implemented Security Check for Standard)

## Which versions are affected by CVE-2020-25684?

It affects 4 products.


Products: Arista Eos, Debian Debian Linux, Fedoraproject Fedora, Thekelleys Dnsmasq.

## How do I fix CVE-2020-25684?

Upgrade to a fixed version.

## Is CVE-2020-25684 being exploited?

There is no known exploitation of CVE-2020-25684 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2026-7473](https://insights.sbomify.com/CVE-2026-7473/): Arista Extensible Operating System Incomplete Comparison with Missing Factors (medium 6.9, exploited in the wild)
- [CVE-2015-8236](https://insights.sbomify.com/CVE-2015-8236/): Privilege escalation in n/a (critical 10.0)
- [CVE-2020-10188](https://insights.sbomify.com/CVE-2020-10188/): Memory corruption in n/a (critical 9.8)
- [CVE-2017-18017](https://insights.sbomify.com/CVE-2017-18017/): Use after free in n/a (critical 9.8)
- [CVE-2017-14491](https://insights.sbomify.com/CVE-2017-14491/): Memory corruption in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-25684 and fix it if it is affected.

What it is: CVE-2020-25684 is a low-severity vulnerability in Debian Debian Linux, published on 20 Jan 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-25684 in the wild and no public exploit code.

Affected product: Debian Debian Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2020-25684/ (Markdown: https://insights.sbomify.com/CVE-2020-25684/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-25684
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-25684
- OSV: https://osv.dev/vulnerability/CVE-2020-25684

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-25684/
Summaries are generated and may contain mistakes; the official description above is the record.