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Vulnerabilities

Vulnerability · CVE-2019-18224

idn2_to_ascii_4i in lib/lookup.c in GNU libidn2 before 2.1.1 has a heap-based buffer overflow via a long domain string.

Published Oct 21, 2019 · catalog updated Oct 14, 2026 · idn2_to_ascii_4i in lib/lookup.c in

Check if you run it

No confirmed exploitation is on record for CVE-2019-18224. EPSS is 3.71%. Act only if a listed version of idn2_to_ascii_4i in lib/lookup.c in is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (idn2_to_ascii_4i in lib/lookup.c in).
  • 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
Critical9.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
3.71%
Remediation
Advisory link
Affected products
cpe gnu/libidn2

idn2_to_ascii_4i in lib/lookup.c in GNU libidn2 before 2.1.1 has a heap-based buffer overflow via a long domain string.

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-2019-18224

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-2019-18224. EPSS is 3.71%. Act only if a listed version of idn2_to_ascii_4i in lib/lookup.c in 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-787: Out-of-bounds Write. EPSS 3.71%. 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 21, 2019 · NIST NVD

    Detected

    idn2_to_ascii_4i in lib/lookup.c in GNU libidn2 before 2.1.1 has a heap-based buffer overflow via a long domain string.

  2. Oct 14, 2026 · NIST NVD

    Updated

    idn2_to_ascii_4i in lib/lookup.c in GNU libidn2 before 2.1.1 has a heap-based buffer overflow via a long domain string.

Sources

  • CVE.orgVulnerability recordCVE-2019-18224

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2019-18224

    30-day exploitation probability 3.7%

    first.org
  • NIST NVDVulnerability recordCVE-2019-18224

    idn2_to_ascii_4i in lib/lookup.c in GNU libidn2 before 2.1.1 has a heap-based buffer overflow via a long domain string.

    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.