SPV Merkle proof malleability allows the maintainer to prove invalid transactions

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

not scored

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary By publishing specially crafted transactions on the Bitcoin blockchain, the SPV maintainer can produce seemingly valid SPV proofs for fraudulent transactions. The issue was originally identified by Least Authority in the tBTC Bridge V2 Security Audit Report as Issue B: Bitcoin SPV Merkle Proofs Can Be Faked. A mitigation was believed to have been in place, but this turned out to contain an error, and the issue had not been effectively mitigated. Details This is achieved by creating a 64-byte transaction that the fraudulent transaction treats as a node in its merkle proof: The attacker creates the malicious transaction E and calculates an unusual but valid transaction D, so that the last 32 bytes of D are a part of the merkle proof of E: foo and bar are arbitrary 32-byte values selected to facilitate this attack. The attacker can then publish D and wait for it to be mined. A valid SPV proof for D can then be transformed into a proof for E by prepending bar and foo to the…

Published by the source

19 Jan 2024, 22:07 UTC

Last modified by the source

19 Jan 2024, 22:07 UTC

Source last checked

26 Oct 2026, 12:30 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-wg2x-rv86-mmpx

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-wg2x-rv86-mmpx

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# Patch Next advisory brief: GHSA-wg2x-rv86-mmpx

Advisory: SPV Merkle proof malleability allows the maintainer to prove invalid transactions
IDs: GHSA-wg2x-rv86-mmpx
Record: https://patchnext.com/advisories/ghsa-wg2x-rv86-mmpx (revision 2, source checked 26 Oct 2026, 12:30 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Unrated
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @keep-network/tbtc-v2 1.5.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @keep-network/tbtc-v2: affected <= 1.5.1; fixed in 1.5.2

## Suggested inspection (read-only)
- `npm ls @keep-network/tbtc-v2 --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @keep-network/tbtc-v2.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-wg2x-rv86-mmpx (OSV record GHSA-wg2x-rv86-mmpx lists affected ranges: npm @keep-network/tbtc-v2 >=0 <1.5.2 (fixed))
- Verified: https://github.com/advisories/GHSA-wg2x-rv86-mmpx (GitHub-reviewed advisory GHSA-wg2x-rv86-mmpx lists affected ranges: npm @keep-network/tbtc-v2 >=0 <=1.5.1)

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