CVE-2025-69287
MEDIUMBSV Blockchain SDK has an Authentication Signature Data Preparation Vulnerability
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
@bsv/sdkReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @bsv/sdk | all versions | 2.0.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @bsv/sdk. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update @bsv/sdk to 2.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-69287 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2025-69287 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2025-69287. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-69287 in your dependencies?
O3 detects CVE-2025-69287 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.