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Vulnerabilities

Vulnerability · CVE-2019-12290

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.

Published Oct 22, 2019 · catalog updated Oct 14, 2026 · GNU libidn2 before 2.2.0

Check if you run it

No confirmed exploitation is on record for CVE-2019-12290. EPSS is 3.23%. Act only if a listed version of GNU libidn2 before 2.2.0 is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (GNU libidn2 before 2.2.0).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
3.23%
Remediation
Advisory link
Affected products
cpe gnu/libidn2

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe gnu/libidn2version unspecified

How to fix CVE-2019-12290

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2019-12290. EPSS is 3.23%. Act only if a listed version of GNU libidn2 before 2.2.0 is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-20: Improper Input Validation. EPSS 3.23%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 22, 2019 · NIST NVD

    Detected

    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 Unicod

  2. Oct 14, 2026 · NIST NVD

    Updated

    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 Unicod

Sources

  • CVE.orgVulnerability recordCVE-2019-12290

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2019-12290

    30-day exploitation probability 3.2%

    first.org
  • NIST NVDVulnerability recordCVE-2019-12290

    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 ex

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 16, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.