CVE Catalog

CVE-2026-107846

CriticalCVSS 9.3
Published: Translated: NVD NIST

Summary

In bitcoinjs-lib (JavaScript Bitcoin library for Node.js and browsers) from 2.3.0 until 5.2.1, 6.1.8, and 7.0.2, fastMerkleRoot pads odd Merkle-tree levels by hashing the final node with itself but does not report adjacent duplicate hashes. Validation paths can accept a recomputed root without checking for mutation, allowing a peer to append duplicate transactions while retaining the original Merkle root, block header, and proof of work.

Risk Assessment

Consumers relying on block-root validation (explorers, exchange indexers, SPV clients) may process a duplicated transaction twice or blacklist the shared block hash and reject the honest block, causing inconsistencies and accounting errors.

Recommendation

Update bitcoinjs-lib to version 5.2.1, 6.1.8, or 7.0.2 and review block-root validation logic in applications.

Related vulnerabilities

Original NVD description (English source)

bitcoinjs-lib is a JavaScript Bitcoin library for Node.js and browsers. From 2.3.0 until 5.2.1, 6.1.8, and 7.0.2, fastMerkleRoot pads odd Merkle-tree levels by hashing the final node with itself but does not report adjacent duplicate hashes. The affected block-root verifier was introduced as Block.checkMerkleRoot() alongside Block.calculateMerkleRoot(), while later versions expose validation through checkTxRoots() and __checkMerkleRoot; these validation paths can accept a recomputed root without checking for mutation. A peer can append duplicate transactions so a different transaction list retains the original Merkle root, block header, proof of work, and block identifier. Consumers that rely on block-root validation, including explorers, exchange indexers, or SPV clients, can process a duplicated transaction twice or blacklist the shared block hash and reject the honest block. This issue is fixed in versions 5.2.1, 6.1.8, and 7.0.2.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS