---
title: "CVE-2019-12290\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2019-12290?format=md
keywords: index, follow
---

# CVE-2019-12290

Publication date 22 October 2019

Last updated 18 August 2025

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**7.5 · High**

[Score breakdown](https://ubuntu.com/security/CVE-2019-12290?format=md#impact-score)

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## 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.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| libidn2-0 | 26.04 LTS resolute | Not in release |
| 25.10 questing | Not in release |
| 25.04 plucky | Not in release |
| 24.10 oracular | Not in release |
| 24.04 LTS noble | Not in release |
| 23.10 mantic | Not in release |
| 23.04 lunar | Not in release |
| 22.10 kinetic | Not in release |
| 22.04 LTS jammy | Not in release |
| 21.10 impish | Not in release |
| 21.04 hirsute | Not in release |
| 20.10 groovy | Not in release |
| 20.04 LTS focal | Not in release |
| 19.10 eoan | Not in release |
| 19.04 disco | Not in release |
| 18.04 LTS bionic | Not in release |
| 16.04 LTS xenial | Vulnerable |
| 14.04 LTS trusty | Vulnerable |
| libidn2 | 26.04 LTS resolute | Not affected |
| 25.10 questing | Not affected |
| 25.04 plucky | Not affected |
| 24.10 oracular | Not affected |
| 24.04 LTS noble | Not affected |
| 23.10 mantic | Not affected |
| 23.04 lunar | Not affected |
| 22.10 kinetic | Not affected |
| 22.04 LTS jammy | Not affected |
| 21.10 impish | Not affected |
| 21.04 hirsute | Not affected |
| 20.10 groovy | Not affected |
| 20.04 LTS focal | Not affected |
| 19.10 eoan | Not affected |
| 19.04 disco | Fixed 2.0.5-1ubuntu0.3 |
| 18.04 LTS bionic | Fixed 2.0.4-1.1ubuntu0.2 |
| 16.04 LTS xenial | Not in release |
| 14.04 LTS trusty | Not in release |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

7.5 · High

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | None |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | None |
  | Integrity impact | High |
  | Availability impact | None |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 7.5 · High |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-12290)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2019-12290)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2019-12290)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2019-12290)

### Related Ubuntu Security Notices (USN)

+ [USN-4168-1](https://usn.ubuntu.com/USN-4168-1)
+ Libidn2 vulnerabilities
+ 29 October 2019

### Other references

* <https://gitlab.com/libidn/libidn2/commit/241e8f486134793cb0f4a5b0e5817a97883401f5>
* <https://gitlab.com/libidn/libidn2/commit/614117ef6e4c60e1950d742e3edf0a0ef8d389de>
* <https://gitlab.com/libidn/libidn2/merge_requests/71>
* <https://www.cve.org/CVERecord?id=CVE-2019-12290>