In the Bouncy Castle JCE Provider version 1.55 and earlier the ECIES implementation allowed the use of ECB mode. This mode is regarded as unsafe and support for it has been removed from the provider.
https://access.redhat.com/errata/RHSA-2018:2669
https://access.redhat.com/errata/RHSA-2018:2927
https://github.com/bcgit/bc-java/commit/9385b0ebd277724b167fe1d1456e3c112112be1f
Source: MITRE
Published: 2018-06-04
Updated: 2020-10-20
Type: CWE-310
Base Score: 5.8
Vector: AV:N/AC:M/Au:N/C:P/I:P/A:N
Impact Score: 4.9
Exploitability Score: 8.6
Severity: MEDIUM
Base Score: 7.4
Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Impact Score: 5.2
Exploitability Score: 2.2
Severity: HIGH