{"id":"CVE-2021-21271","aliases":["EUVD-2022-7141","GHSA-p658-8693-mhvg","GO-2022-1052"],"status":"published","title":"Denial of service in TenderMint Core","description":"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.","severity":{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.01763,"percentile":0.78225,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-400"],"published":"2021-01-26T20:55:14Z","modified":"2026-10-20T10:54:27Z","fixes":[{"ecosystem":"Go","package":"github.com/tendermint/tendermint","fixed_in":["0.34.3"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Go","package":"github.com/tendermint/tendermint","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0.34.0"},{"fixed":"0.34.3"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/tendermint/tendermint","ranges":[{"type":"SEMVER","events":[{"introduced":"0.34.0"},{"fixed":"0.34.3"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/tendermint/tendermint","ranges":[{"type":"SEMVER","events":[{"introduced":"0.34.0"},{"fixed":"0.34.3"}]}]}],"products":[{"vendor":"tendermint","product":"tendermint"}],"references":[{"url":"https://github.com/tendermint/tendermint/security/advisories/GHSA-p658-8693-mhvg","tags":["x_refsource_CONFIRM","x_transferred","Third Party Advisory","advisory","web"]},{"url":"https://github.com/tendermint/tendermint/blob/v0.34.3/CHANGELOG.md#v0.34.3","tags":["x_refsource_MISC","x_transferred","Release Notes","Third Party Advisory","advisory","web","article"]},{"url":"https://github.com/tendermint/tendermint/commit/a2a6852ab99e4a0f9e79f0ea8c1726e262e25c76","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","fix","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-21271","tags":["advisory"]},{"url":"https://pkg.go.dev/vuln/GO-2022-1052","tags":["web"]},{"url":"https://github.com/tendermint/tendermint/pull/5219","tags":["web"]},{"url":"https://github.com/advisories/GHSA-p658-8693-mhvg"},{"url":"https://github.com/tendermint/tendermint","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2021-21271","title":"Denial of service in TenderMint Core","description":"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.","status":"published","published":"2021-01-26T20:55:14Z","modified":"2024-08-03T18:09:15.015Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna"}],"cwes":["CWE-400"],"updated_at":"2026-11-02T14:33:00.488332Z"}],"euvd":[{"id":"EUVD-2022-7141","description":"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.","status":"published","published":"2021-01-26T20:55:14Z","modified":"2024-08-03T18:09:15Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-03T03:25:06.347262Z"}],"ghsa":[{"id":"GHSA-p658-8693-mhvg","title":"Tendermint Core vulnerable to Uncontrolled Resource Consumption","description":"### Description \n\nTendermint 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](https://github.com/tendermint/tendermint/pull/5219). 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.) \n\nIn 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.`\n\nIn 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. \n\nTendermint 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 `Vote`s 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. \n\nThis release changes the API between the `consensus` and `evidence` reactors. \n\n### Impact\n\nThis is a denial-of-service vector which impacts networks running Tendermint Core v0.34.0 - v0.34.2.\n\n### Remediation\n\nThis problem has been patched in Tendermint Core v0.34.3. Networks running impacted versions of Tendermint Core should update immediately.\n\n### Workarounds\n\nThere are no workarounds, other than upgrading to a patched version of Tendermint Core.\n\n### Credits \n\n* Crypto.com (@cyril-crypto, @brianatcrypto, @tomtau and  @yihuang) for finding and submitting this vulnerability\n* @melekes and @cmwaters for identifying the root cause and patching the problem \n\n### For more information\n\nIf you have any questions or comments about this advisory:\n* Open an issue in [tendermint/tendermint](https://github.com/tendermint/tendermint)\n* Email us at [security@tendermint.com](mailto:security@tendermint.com)","status":"published","published":"2022-10-07T07:23:51Z","modified":"2024-05-31T16:54:41Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-400"],"updated_at":"2026-11-02T14:37:53.025064Z"}],"nvd":[{"id":"CVE-2021-21271","description":"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.","status":"published","published":"2021-01-26T21:15:12.503Z","modified":"2026-06-17T03:35:09.9Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"secondary"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"primary"},{"version":"2.0","score":4,"vector":"AV:N/AC:L/Au:S/C:N/I:N/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-400"],"updated_at":"2026-11-02T14:06:49.660551Z"}],"osv":[{"id":"CVE-2021-21271","description":"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.","status":"published","published":"2021-01-26T21:15:12.503Z","modified":"2026-10-20T10:54:27.762218858Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:44:18.004149Z"},{"id":"GHSA-p658-8693-mhvg","title":"Tendermint Core vulnerable to Uncontrolled Resource Consumption","description":"### Description \n\nTendermint 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](https://github.com/tendermint/tendermint/pull/5219). 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.) \n\nIn 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.`\n\nIn 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. \n\nTendermint 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 `Vote`s 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. \n\nThis release changes the API between the `consensus` and `evidence` reactors. \n\n### Impact\n\nThis is a denial-of-service vector which impacts networks running Tendermint Core v0.34.0 - v0.34.2.\n\n### Remediation\n\nThis problem has been patched in Tendermint Core v0.34.3. Networks running impacted versions of Tendermint Core should update immediately.\n\n### Workarounds\n\nThere are no workarounds, other than upgrading to a patched version of Tendermint Core.\n\n### Credits \n\n* Crypto.com (@cyril-crypto, @brianatcrypto, @tomtau and  @yihuang) for finding and submitting this vulnerability\n* @melekes and @cmwaters for identifying the root cause and patching the problem \n\n### For more information\n\nIf you have any questions or comments about this advisory:\n* Open an issue in [tendermint/tendermint](https://github.com/tendermint/tendermint)\n* Email us at [security@tendermint.com](mailto:security@tendermint.com)","status":"published","published":"2022-10-07T07:23:51Z","modified":"2026-07-08T06:00:48.96845928Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-400"],"updated_at":"2026-11-02T15:46:52.891208Z"},{"id":"GO-2022-1052","title":"Uncontrolled resource consumption during consensus in github.com/tendermint/tendermint","description":"Mishandling of timestamps during consensus process can cause a denial of service.\n\nWhile reaching consensus, different tendermint nodes can observe a different timestamp for a consensus evidence. This mismatch can cause the evidence to be invalid, upon which the node producing the evidence will be asked to generate a new evidence. This new evidence will be the same, which means it will again be rejected by other nodes involved in the consensus. This loop will continue until the peer nodes decide to disconnect from the node producing the evidence.","status":"published","published":"2022-10-14T23:59:50Z","modified":"2024-05-20T16:03:47Z","updated_at":"2026-11-02T15:47:00.918515Z"}]}}