# CVE-2019-6475: A flaw in mirror zone validity checking can allow zone data to be spoofed

> An on-path attacker can spoof DNS data in BIND mirror zones by bypassing validity checks, requiring the mirror zone feature to be enabled.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/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:** 17 Oct 2019
- **Updated:** 16 Sep 2024
- **Also known as:** ALPINE-CVE-2019-6475, GHSA-2gfp-93f7-f268

## What is CVE-2019-6475?

CVE-2019-6475 is a medium-severity vulnerability in Isc Bind, published on 17 Oct 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Mirror zones are a BIND feature allowing recursive servers to pre-cache zone data provided by other servers. A mirror zone is similar to a zone of type secondary, except that its data is subject to DNSSEC validation before being used in answers, as if it had been looked up via traditional recursion, and when mirror zone data cannot be validated, BIND falls back to using traditional recursion instead of the mirror zone. However, an error in the validity checks for the incoming zone data can allow an on-path attacker to replace zone data that was validated with a configured trust anchor with forged data of the attacker's choosing. The mirror zone feature is most often used to serve a local copy of the root zone. If an attacker was able to insert themselves into the network path between a recursive server using a mirror zone and a root name server, this vulnerability could then be used to cause the recursive server to accept a copy of falsified root zone data. This affects BIND versions 9.14.0 up to 9.14.6, and 9.15.0 up to 9.15.4.

Weakness: CWE-345 (Insufficient Verification of Data Authenticity)

## Which versions are affected by CVE-2019-6475?

It affects 1 product.


Products: Isc Bind.

## How do I fix CVE-2019-6475?

Upgrade to a fixed version.

## Is CVE-2019-6475 being exploited?

There is no known exploitation of CVE-2019-6475 in the wild and no public exploit code.

## Other vulnerabilities in Isc Bind

- [CVE-2008-0122](https://insights.sbomify.com/CVE-2008-0122/): Memory corruption in n/a (critical 10.0)
- [CVE-2001-0010](https://insights.sbomify.com/CVE-2001-0010/): Memory corruption in n/a (critical 10.0)
- [CVE-2001-0011](https://insights.sbomify.com/CVE-2001-0011/): Memory corruption in n/a (critical 10.0)
- [CVE-2001-0013](https://insights.sbomify.com/CVE-2001-0013/): Memory corruption in n/a (critical 10.0)
- [CVE-2000-1029](https://insights.sbomify.com/CVE-2000-1029/): Memory corruption in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-6475 and fix it if it is affected.

What it is: CVE-2019-6475 is a medium-severity vulnerability in Isc Bind, published on 17 Oct 2019. 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-2019-6475 in the wild and no public exploit code.

Affected product: Isc Bind. 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-2019-6475/ (Markdown: https://insights.sbomify.com/CVE-2019-6475/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-6475
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-6475
- OSV: https://osv.dev/vulnerability/CVE-2019-6475

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-6475/
Summaries are generated and may contain mistakes; the official description above is the record.