CVE-2025-69287

What it is

The BSV Blockchain SDK is a unified TypeScript SDK for developing scalable apps on the BSV Blockchain. Prior to version 2.0.0, a cryptographic vulnerability in the TypeScript SDK's BRC-104 authentication implementation caused incorrect signature data preparation, resulting in signature incompatibility between SDK implementations and potential authentication bypass scenarios. The vulnerability was located in the `Peer.ts` file of the TypeScript SDK, specifically in the `processInitialRequest` and `processInitialResponse` methods where signature data is prepared for BRC-104 mutual authentication. The TypeScript SDK incorrectly prepared signature data by concatenating base64-encoded nonce strings (`message.initialNonce + sessionNonce`) then decoding the concatenated base64 string (`base64ToBytes(concatenatedString)`). This produced ~32-34 bytes of signature data instead of the correct 64 bytes. BRC-104 authentication relies on cryptographic signatures to establish mutual trust between peers. When signature data preparation is incorrect, signatures generated by the TypeScript SDK don't match those expected by Go/Python SDKs; cross-implementation authentication fails; and an attacker could potentially exploit this to bypass authentication checks. The fix in version 2.0.0 ensures all SDKs now produce identical cryptographic signatures, restoring proper mutual authentication across implementations.

At a glance

Exploitability

Can be exploited over the network without logging in, but needs a user to act. Limited direct impact.

Exploit odds

0.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-02-18 19:21 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 10:00 UTC Last updatedMost recent change to the record

Details

Published

2026-02-18 19:21 UTC

Last modified

2026-06-17 10:00 UTC

Exploit probability

0.3% · EPSS, next 30 days

Weakness

CWE-573

Record status

Deferred

Attack profile CVSS 3.1 · 5.4

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

Low