What’s Vulnerable › Vulnerabilities
CVE-2019-12290
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 3.2% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2019-10-22 · updated 2026-10-14
- Weakness: CWE-20
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.
Affected products
- GNU Libidn2: before 2.2.0 — fixed in 2.2.0
How to fix
Upgrade to a fixed version: GNU Libidn2 2.2.0. Check the vendor advisory for mitigations.
References
- http://lists.opensuse.org/opensuse-security-announce/2019-12/msg00008.html
- http://lists.opensuse.org/opensuse-security-announce/2019-12/msg00009.html
- https://gitlab.com/libidn/libidn2/commit/241e8f486134793cb0f4a5b0e5817a97883401f5
- https://gitlab.com/libidn/libidn2/commit/614117ef6e4c60e1950d742e3edf0a0ef8d389de
- https://gitlab.com/libidn/libidn2/merge_requests/71
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3UFT76Y7OSGPZV3EBEHD6ISVUM3DLARM/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KXDKYWFV6N2HHVSE67FFDM7G3FEL2ZNE/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ONG3GJRRJO35COPGVJXXSZLU4J5Y42AT/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RSI4TI2JTQWQ3YEUX5X36GTVGKO4QKZ5/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/U6ZXL2RDNQRAHCMKWPOMJFKYJ344X4HL/
- https://security.gentoo.org/glsa/202003-63
- https://usn.ubuntu.com/4168-1/
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