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0xCERT Security Advisory 0xCERT-2026-0217
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Advisory-ID:  0xCERT-2026-0217
Severity:     High
Published:    2026-01-23T16:56:23.000Z
Updated:      2026-10-08T22:48:25.826Z
Chains:       Cosmos Hub
URL:          https://www.0xcert.com/advisory/0xCERT-2026-0217

Title: CometBFT has inconsistencies between how commit signatures are verified and how block time is derived

Summary
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CometBFT has inconsistencies between how commit signatures are verified and how block time is derived. Name: CSA-2026-001: Tachyon Criticality: Critical (Catastrophic Impact; Possible Likelihood per ACMv1.

Details
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Summary
Name: CSA-2026-001: Tachyon Criticality: Critical (Catastrophic Impact; Possible Likelihood per ACMv1.2) Affected versions: All versions of CometBFT Affected users: Validators and protocols relying on block timestamps A consensus-level vulnerability was discovered in CometBFT's "BFT Time" implementation due to an inconsistency between how commit signatures are verified and how block time is derived.

Affected
- - github.com/cometbft/cometbft (go) >= 0.38.0-alpha.1, <= 0.38.20 — fixed in 0.38.21
- - github.com/cometbft/cometbft (go) <= 0.37.17 — fixed in 0.37.18

Severity
High (CVSS 7.1), as rated by the upstream advisory.

Recommended actions
- - Upgrade github.com/cometbft/cometbft to 0.38.21 or later
- - Upgrade github.com/cometbft/cometbft to 0.37.18 or later

Source & attribution
This 0xCERT advisory summarises GHSA-c32p-wcqj-j677 from the GitHub Advisory Database: https://github.com/advisories/GHSA-c32p-wcqj-j677. Details may change; refer to the original source for the authoritative record.

References
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- - https://github.com/advisories/GHSA-c32p-wcqj-j677
- - https://github.com/cometbft/cometbft/security/advisories/GHSA-c32p-wcqj-j677
- - https://github.com/cometbft/cometbft/commit/bf8274fcdbcab2bc652660ae627196a90a6efb97
- - https://github.com/cometbft/cometbft/releases/tag/v0.37.18
- - https://github.com/cometbft/cometbft/releases/tag/v0.38.21
- - https://pkg.go.dev/vuln/GO-2026-4361

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