{"id":"CVE-2025-69287","state":"PUBLISHED","title":"BSV Blockchain SDK has an Authentication Signature Data Preparation Vulnerability","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.","publishedAt":"2026-02-18T18:42:22.893Z","updatedAt":"2026-02-18T19:26:38.840Z","severity":{"score":5.4,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L","source":"GitHub_M"},"assigner":"GitHub_M","products":["bsv-blockchain ts-sdk"],"affected":[{"vendor":"bsv-blockchain","product":"ts-sdk","versions":[{"version":"< 2.0.0","status":"affected"}]}],"references":["https://github.com/bsv-blockchain/ts-sdk/security/advisories/GHSA-vjpq-xx5g-qvmm","https://github.com/bsv-blockchain/ts-sdk/commit/d8cf6930028372079d977138ae9eaa03ae2f50bb"],"weaknesses":["CWE-573"],"ingestedAt":"2026-10-29T20:09:56.034Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/69xxx/CVE-2025-69287.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-69287","state":"PUBLISHED","datePublished":"2026-02-18T18:42:22.893Z","dateUpdated":"2026-02-18T19:26:38.840Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2025-12-31T16:38:21.806Z"},"containers":{"cna":{"title":"BSV Blockchain SDK has an Authentication Signature Data Preparation Vulnerability","descriptions":[{"lang":"en","value":"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":[{"vendor":"bsv-blockchain","product":"ts-sdk","versions":[{"version":"< 2.0.0","status":"affected"}]}],"references":[{"url":"https://github.com/bsv-blockchain/ts-sdk/security/advisories/GHSA-vjpq-xx5g-qvmm","name":"https://github.com/bsv-blockchain/ts-sdk/security/advisories/GHSA-vjpq-xx5g-qvmm","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/bsv-blockchain/ts-sdk/commit/d8cf6930028372079d977138ae9eaa03ae2f50bb","name":"https://github.com/bsv-blockchain/ts-sdk/commit/d8cf6930028372079d977138ae9eaa03ae2f50bb","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":5.4,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-573","lang":"en","description":"CWE-573: Improper Following of Specification by Caller","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-02-18T18:42:22.893Z"},"source":{"advisory":"GHSA-vjpq-xx5g-qvmm","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-02-18T19:26:20.981064Z","id":"CVE-2025-69287","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-02-18T19:26:38.840Z"}}]}}}