Blst versions v0.3.0 to v0.3.2 can produce the incorrect outputs for some inputs to the blstfpeucl_inverse function. This could theoretically result in the creation of an invalid signature from correct inputs. However, fuzzing of higher level functions such as sign and verify were unable to produce incorrect results and there has been no reported occurrences of this issue being encountered in production use.
During the course of differential fuzzing of the blst library by @guidovranken it was discovered that blst would produce the incorrect result for some input values in the inverse function. This was the result of the introduction of a new inversion formula in version v0.3.0. This source of these incorrect outputs was due to two issues:
This issue has been resolved in the v0.3.3 release and users are recommended to upgrade immediately.
The software used to uncover this issue can be found here.
A special thanks to Guido Vranken (@guidovranken) for his discovery and disclosure of this vulnerability.
If you have any questions or comments about this advisory please email us at hello@supranational.net
{ "nvd_published_at": null, "github_reviewed": true, "github_reviewed_at": "2022-10-07T07:25:33Z", "severity": "MODERATE", "cwe_ids": [] }