CVEvulnerability

CVE-2021-21405

7.5 HIGH Published 2021-04-15 Modified 2026-06-17 Official page ↗
Status
Modified
Published
2021-04-15
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
5.9 MEDIUM — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS 3.1 ([email protected])
7.5 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS 2.0 ([email protected])
5.0 MEDIUM — AV:N/AC:L/Au:N/C:N/I:P/A:N
Weaknesses
CWE-347

Description

Lotus is an Implementation of the Filecoin protocol written in Go. BLS signature validation in lotus uses blst library method VerifyCompressed. This method accepts signatures in 2 forms: "serialized", and "compressed", meaning that BLS signatures can be provided as either of 2 unique byte arrays. Lotus block validation functions perform a uniqueness check on provided blocks. Two blocks are considered distinct if the CIDs of their blockheader do not match. The CID method for blockheader includes the BlockSig of the block. The result of these issues is that it would be possible to punish miners for valid blocks, as there are two different valid block CIDs available for each block, even though this must be unique. By switching from the go based `blst` bindings over to the bindings in `filecoin-ffi`, the code paths now ensure that all signatures are compressed by size and the way they are deserialized. This happened in https://github.com/filecoin-project/lotus/pull/5393.

Affected configurations

• filecoin lotus (< 1.5.0)

Related

Weakness · CWE (1)

  • CWE-347 Improper Verification of Cryptographic Signature weakness

References