# CVE-2019-12290: Other in n/a

> Attackers can impersonate arbitrary domains by exploiting missing roundtrip checks in libidn2, bypassing domain validation mechanisms.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/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:** 22 Oct 2019
- **Updated:** 14 Oct 2026
- **Also known as:** ALPINE-CVE-2019-12290, CLEANSTART-2024-IG59808, DEBIAN-CVE-2019-12290, GHSA-5pjp-55fh-7frw, UBUNTU-CVE-2019-12290

## What is CVE-2019-12290?

CVE-2019-12290 is a high-severity vulnerability in n/a, published on 22 Oct 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

GNU libidn2 before 2.2.0 fails to perform the roundtrip checks specified in RFC3490 Section 4.2 when converting A-labels to U-labels. This makes it possible in some circumstances for one domain to impersonate another. By creating a malicious domain that matches a target domain except for the inclusion of certain punycoded Unicode characters (that would be discarded when converted first to a Unicode label and then back to an ASCII label), arbitrary domains can be impersonated.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2019-12290?

It affects 1 product.


Products: Gnu Libidn2.

## How do I fix CVE-2019-12290?

Upgrade to a fixed version.

## Is CVE-2019-12290 being exploited?

There is no known exploitation of CVE-2019-12290 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2019-18224](https://insights.sbomify.com/CVE-2019-18224/): Memory corruption in n/a (critical 9.8)
- [CVE-2017-14061](https://insights.sbomify.com/CVE-2017-14061/): Integer overflow in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-12290 and fix it if it is affected.

What it is: CVE-2019-12290 is a high-severity vulnerability in n/a, published on 22 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-2019-12290 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-2019-12290/ (Markdown: https://insights.sbomify.com/CVE-2019-12290/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-12290
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-12290
- OSV: https://osv.dev/vulnerability/CVE-2019-12290

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-12290/
Summaries are generated and may contain mistakes; the official description above is the record.