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.

CVSS 3.1

9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

3.7% chance of exploitation in the next 30 days; higher than 89% of CVEs (scores of 2026-10-25)

CWE

CWE-787

Published

2019-10-21

Modified

2026-10-14

Record from

the NVD, synced 2026-10-19

Affected

• gnu:libidn2

References

• http://lists.opensuse.org/opensuse-security-announce/2019-12/msg00008.html
• http://lists.opensuse.org/opensuse-security-announce/2019-12/msg00009.html
• https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=12420
• https://github.com/libidn/libidn2/commit/e4d1558aa2c1c04a05066ee8600f37603890ba8c
• https://github.com/libidn/libidn2/compare/libidn2-2.1.0...libidn2-2.1.1

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