# CVE-2026-19941: checkwildcard() accepts an out-of-zone NSEC as a wildcard-nonexistence proof

> Attackers can mask wildcard records by exploiting NSEC validation flaws in BIND, potentially hiding DNS data from resolvers.

- **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:** 16 Sep 2026
- **Updated:** 17 Sep 2026
- **Also known as:** ALPINE-CVE-2026-19941, AZL-103359, BELL-CVE-2026-19941, DEBIAN-CVE-2026-19941, ECHO-9873-7113-c63e, GHSA-38fx-cm5x-27pg, MINI-6h24-9xc7-vqj4, MINI-wx56-m8x3-56cj, MINI-wxh2-g7gh-2qvc, UBUNTU-CVE-2026-19941

## What is CVE-2026-19941?

CVE-2026-19941 is a medium-severity vulnerability in ISC BIND 9, published on 16 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An inapplicable NSEC record may be accepted by a `named` resolver as proof that no wildcard exists, which could allow an attacker at the same or an upstream level of the zone name to mask the existence of a victim's wildcard record.
This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.

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

## Which versions are affected by CVE-2026-19941?


## How do I fix CVE-2026-19941?

Apply the vendor's patch.

## Is CVE-2026-19941 being exploited?

There is no known exploitation of CVE-2026-19941 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-19941 and fix it if it is affected.

What it is: CVE-2026-19941 is a medium-severity vulnerability in ISC BIND 9, published on 16 Sep 2026. 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-2026-19941 in the wild and no public exploit code.

Affected product: ISC BIND 9. 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-2026-19941/ (Markdown: https://insights.sbomify.com/CVE-2026-19941/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-19941
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-19941
- OSV: https://osv.dev/vulnerability/CVE-2026-19941

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-19941/
Summaries are generated and may contain mistakes; the official description above is the record.