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.
2019-10-22T16:15:10.877
2024-11-21T04:22:33.913
Modified
CVSSv3.1: 7.5 (HIGH)
AV:N/AC:L/Au:N/C:N/I:P/A:N
10.0
2.9