# CVE-2020-8618: A buffer boundary check assertion in rdataset.c can fail incorrectly during zone transfer

> An attacker can cause a denial of service in BIND9 by triggering an assertion failure during zone transfers with specially crafted data.

- **Severity:** Medium 4.9 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Jun 2020
- **Updated:** 16 Sep 2024
- **Also known as:** ALPINE-CVE-2020-8618, DEBIAN-CVE-2020-8618, GHSA-2c3j-p34f-v2cr, UBUNTU-CVE-2020-8618

## What is CVE-2020-8618?

CVE-2020-8618 is a medium-severity denial of service vulnerability in Canonical Ubuntu Linux, published on 17 Jun 2020. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

An attacker who is permitted to send zone data to a server via zone transfer can exploit this to intentionally trigger the assertion failure with a specially constructed zone, denying service to clients.

Weakness: CWE-617 (Reachable Assertion)

## Which versions are affected by CVE-2020-8618?

It affects 4 products.


Products: Canonical Ubuntu Linux, Isc Bind, Netapp Steelstore Cloud Integrated Storage, Opensuse Leap.

## How do I fix CVE-2020-8618?

Apply the vendor's patch.

## Is CVE-2020-8618 being exploited?

There is no known exploitation of CVE-2020-8618 in the wild and no public exploit code.

## Other vulnerabilities in Canonical Ubuntu Linux

- [CVE-2020-11651](https://insights.sbomify.com/CVE-2020-11651/): SaltStack Salt Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2020-7247](https://insights.sbomify.com/CVE-2020-7247/): OpenSMTPD Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2019-16928](https://insights.sbomify.com/CVE-2019-16928/): Exim Out-of-bounds Write (critical 9.8, exploited in the wild)
- [CVE-2018-6789](https://insights.sbomify.com/CVE-2018-6789/): Exim Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2015-2590](https://insights.sbomify.com/CVE-2015-2590/): Oracle Java SE and Java SE Embedded Remote Code Execution (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-8618 and fix it if it is affected.

What it is: CVE-2020-8618 is a medium-severity denial of service vulnerability in Canonical Ubuntu Linux, published on 17 Jun 2020. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-8618 in the wild and no public exploit code.

Affected product: Canonical Ubuntu 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-2020-8618/ (Markdown: https://insights.sbomify.com/CVE-2020-8618/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-8618
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-8618
- OSV: https://osv.dev/vulnerability/CVE-2020-8618

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-8618/
Summaries are generated and may contain mistakes; the official description above is the record.