Tendermint Core is an open source Byzantine Fault Tolerant (BFT) middleware that takes a state transition machine - written in any programming language - and securely replicates it on many machines. Tendermint Core v0.34.0 introduced a new way of handling evidence of misbehavior. As part of this, we added a new Timestamp field to Evidence structs. This timestamp would be calculated using the same algorithm that is used when a block is created and proposed. (This algorithm relies on the timestamp of the last commit from this specific block.) In Tendermint Core v0.34.0-v0.34.2, the consensus reactor is responsible for forming DuplicateVoteEvidence whenever double signs are observed. However, the current block is still “in flight” when it is being formed by the consensus reactor. It hasn’t been finalized through network consensus yet. This means that different nodes in the network may observe different “last commits” when assigning a timestamp to DuplicateVoteEvidence. In turn, different nodes could form DuplicateVoteEvidence objects at the same height but with different timestamps. One DuplicateVoteEvidence object (with one timestamp) will then eventually get finalized in the block, but this means that any DuplicateVoteEvidence with a different timestamp is considered invalid. Any node that formed invalid DuplicateVoteEvidence will continue to propose invalid evidence; its peers may see this, and choose to disconnect from this node. This bug means that double signs are DoS vectors in Tendermint Core v0.34.0-v0.34.2. Tendermint Core v0.34.3 is a security release which fixes this bug. As of v0.34.3, DuplicateVoteEvidence is no longer formed by the consensus reactor; rather, the consensus reactor passes the Votes themselves into the EvidencePool, which is now responsible for forming DuplicateVoteEvidence. The EvidencePool has timestamp info that should be consistent across the network, which means that DuplicateVoteEvidence formed in this reactor should have consistent timestamps. This release changes the API between the consensus and evidence reactors.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - Tendermint Core is an open source Byzantine Fault Tolerant (BFT) middleware that takes a state transition
    machine - written in any programming language - and securely replicates it on many machines. Tendermint
    Core v0.34.0 introduced a new way of handling evidence of misbehavior. As part of this, we added a new
    Timestamp field to Evidence structs. This timestamp would be calculated using the same algorithm that is
    used when a block is created and proposed. (This algorithm relies on the timestamp of the last commit from
    this specific block.) In Tendermint Core v0.34.0-v0.34.2, the consensus reactor is responsible for forming
    DuplicateVoteEvidence whenever double signs are observed. However, the current block is still “in flight”
    when it is being formed by the consensus reactor. It hasn’t been finalized through network consensus yet.
    This means that different nodes in the network may observe different “last commits” when assigning a
    timestamp to DuplicateVoteEvidence. In turn, different nodes could form DuplicateVoteEvidence objects at
    the same height but with different timestamps. One DuplicateVoteEvidence object (with one timestamp) will
    then eventually get finalized in the block, but this means that any DuplicateVoteEvidence with a different
    timestamp is considered invalid. Any node that formed invalid DuplicateVoteEvidence will continue to
    propose invalid evidence; its peers may see this, and choose to disconnect from this node. This bug means
    that double signs are DoS vectors in Tendermint Core v0.34.0-v0.34.2. Tendermint Core v0.34.3 is a
    security release which fixes this bug. As of v0.34.3, DuplicateVoteEvidence is no longer formed by the
    consensus reactor; rather, the consensus reactor passes the Votes themselves into the EvidencePool, which
    is now responsible for forming DuplicateVoteEvidence. The EvidencePool has timestamp info that should be
    consistent across the network, which means that DuplicateVoteEvidence formed in this reactor should have
    consistent timestamps. This release changes the API between the consensus and evidence reactors.
    (CVE-2021-21271)

ID	Name	Product	Family	Type	Severity
433659	SCA: security update for github.com/tendermint/tendermint (GHSA-p658-8693-mhvg)	Tenable Cloud Security	SCA Checks	Local	medium
433659	SCA: security update for github.com/tendermint/tendermint (GHSA-p658-8693-mhvg)	Tenable Self-Hosted Container Security	SCA Checks	Local	medium

Detections

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CVE-2021-21271

medium

Tenable Plugins

medium

medium