The ECDSA implementation of the Elliptic package generates incorrect signatures if an interim value of 'k' (as computed based on step 3.2 of RFC 6979 https://datatracker.ietf.org/doc/html/rfc6979 ) has leading zeros and is susceptible to cryptanalysis, which can lead to secret key exposure. This happens, because the byte-length of 'k' is incorrectly computed, resulting in its getting truncated during the computation. Legitimate transactions or communications will be broken as a result. Furthermore, due to the nature of the fault, attackers could–under certain conditions–derive the secret key, if they could get their hands on both a faulty signature generated by a vulnerable version of Elliptic and a correct signature for the same inputs.
This issue affects all known versions of Elliptic (at the time of writing, versions less than or equal to 6.6.1).
{
"github_reviewed": true,
"github_reviewed_at": "2026-01-09T20:19:43Z",
"severity": "LOW",
"nvd_published_at": "2026-01-08T21:15:42Z",
"cwe_ids": [
"CWE-1240"
]
}