Security: Implement Blockchain Reorganization Detection for Transaction Confirmations

[Smartdevs17]

Context

Blockchain reorganizations can reverse confirmed transactions. AgenticPay must wait for sufficient confirmations but also detect and handle reorgs properly.

Current Limitation/Problem

The system uses a fixed confirmation count without monitoring for chain reorganizations. If a reorg occurs deeper than the confirmation threshold, the system incorrectly treats transactions as final.

Expected Outcome

A reorg detection service that monitors for chain reorganizations beyond the safety threshold, marks affected transactions for review, and triggers remediation workflows.

Acceptance Criteria

• Monitor new blocks for chain reorganization events (different parent hash)
• Track reorg depth and affected transactions
• Configurable confirmation thresholds per chain (Ethereum: 12, Polygon: 64, Stellar: 1)
• Alert on reorgs deeper than safety margin
• Mark affected transactions as pending_review with reorg details
• Automatic re-verification of affected transaction status
• Dashboard showing reorg events and affected transactions
• History of past reorg incidents with resolution status
• Test: simulate reorgs in integration tests

Technical Scope

• backend/src/services/chain/reorg-detector.ts - reorg detection
• backend/src/services/chain/confirmation-tracker.ts - confirmation management
• Prisma: ReorgEvent, TransactionReorg models
• BullMQ queue for reorg processing
• Integration with existing transaction status service
• Edge cases: deep reorgs (>100 blocks), chain splits, orphaned blocks, uncle blocks

[lekanay2005-coder]

@lekanay2005-coder has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi maintainer. I am interested in this issue.

I have experience working across frontend, backend, smart contracts, and developer tooling, and I’m comfortable making targeted fixes and improvements in existing codebases. I’ll ensure the implementation is clean, tested, and aligned with the project requirements.

Thanks!

ℹ️ Repo Maintainers: To accept this application, review their application or assign @lekanay2005-coder to this issue.

[Timothy2025-20]

@Timothy2025-20 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

HI Maintainer, am a software engineer with years of experience and an enthusiast in open source projects. I will really like to resolve this issue if assigned to me. Thank you

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Timothy2025-20 to this issue.

[primexk5]

@primexk5 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Gm maintainer, please I'd like to work on this issue, assign it to me and I'll return a PR shortly.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @primexk5 to this issue.

[drips-wave]

Congratulations, @primexk5! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @primexk5: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

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