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.
Platform | Package | Release Date | Advisory |
---|---|---|---|
Amazon Linux 1 | libidn2 | 2019-12-13 21:13 | ALAS-2019-1327 |
Amazon Linux 2 - Core | libidn2 | 2019-12-13 19:34 | ALAS2-2019-1373 |
Score Type | Score | Vector | |
---|---|---|---|
Amazon Linux | CVSSv2 | 5.0 | AV:N/AC:L/Au:N/C:N/I:P/A:N |
Amazon Linux | CVSSv3 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
NVD | CVSSv2 | 5.0 | AV:N/AC:L/Au:N/C:N/I:P/A:N |
NVD | CVSSv3 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |