CVE-2025-69287 BSV Blockchain SDK has an Authentication Signature Data Preparation Vulnerability
Incorrect signature data preparation in the BSV Blockchain SDK allows attackers to bypass mutual authentication checks between peers.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2025-69287?
CVE-2025-69287 is a medium-severity authentication bypass vulnerability in bsv-blockchain ts-sdk, published on 18 Feb 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-573
Which versions are affected by CVE-2025-69287?
2 open source packages ship an affected version, including @bsv/sdk.
| Package | Affected | Fixed in |
|---|---|---|
@bsv/sdk npm | All versions | 2.0.0 |
@bsv/sdk npm | All versions | 2.0.0 |
How do I fix CVE-2025-69287?
Upgrade @bsv/sdk to 2.0.0 or later.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2025-69287 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-69287 exists.
Sources
Also known as GHSA-vjpq-xx5g-qvmm.