# CVE-2020-25767: Denial of service in n/a

> Attackers can cause a denial of service in HCC Embedded NicheStack IPv4 by sending crafted DNS packets with invalid compression pointers.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 18 Aug 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-2hg5-gxv6-8v58

## What is CVE-2020-25767?

CVE-2020-25767 is a high-severity denial of service vulnerability in n/a, published on 18 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered in HCC Embedded NicheStack IPv4 4.1. The dnc_copy_in routine for parsing DNS domain names does not check whether a domain name compression pointer is pointing within the bounds of the packet (e.g., forward compression pointer jumps are allowed), which leads to an Out-of-bounds Read, and a Denial-of-Service as a consequence.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2020-25767?

It affects 1 product.


Products: Hcc-Embedded Nichestack Ipv4.

## How do I fix CVE-2020-25767?

No fix has been published for CVE-2020-25767 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-25767 being exploited?

There is no known exploitation of CVE-2020-25767 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-25767 and fix it if it is affected.

What it is: CVE-2020-25767 is a high-severity denial of service vulnerability in n/a, published on 18 Aug 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-2020-25767 in the wild and no public exploit code.

Affected product: n/a. 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-2020-25767/ (Markdown: https://insights.sbomify.com/CVE-2020-25767/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-25767
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-25767
- OSV: https://osv.dev/vulnerability/CVE-2020-25767

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-25767/
Summaries are generated and may contain mistakes; the official description above is the record.