In the Elliptic package 6.5.6 for Node.js, ECDSA signature malleability occurs because there is a missing check for whether the leading bit of r and s is zero.
{ "binaries": [ { "binary_name": "node-elliptic", "binary_version": "6.4.0+dfsg-1" } ] }
{ "binaries": [ { "binary_name": "node-elliptic", "binary_version": "6.5.1~dfsg-2" } ] }
{ "binaries": [ { "binary_name": "node-elliptic", "binary_version": "6.5.4~dfsg-1" } ] }
{ "binaries": [ { "binary_name": "node-elliptic", "binary_version": "6.5.4~dfsg-2" } ] }
{ "binaries": [ { "binary_name": "node-elliptic", "binary_version": "6.6.1+dfsg-1" } ] }