Summary:
For transparency and to close the loop on an incident, we are posting our analysis and post mortem on a delegation rewards incident that occurred on 7/2/26.
If anyone has any questions or concerns please reach out.
Date: February 7, 2026
Status: Resolved - all affected delegators have been fully compensated.
What happened
Between December 6, 2025 and February 7, 2026, a software bug in our internal keystore configuration tool caused a portion of our attesters to propose blocks with incorrect coinbase addresses. This misrouted block rewards across split contracts, some delegators received less than owed, while others received more.
The bug was a logical error introduced during a routine update to accommodate new validator slots. It caused the keystore entries to be sorted in a way that shifted coinbase assignments across attesters.
This was an operational error on our side. The Aztec protocol and its smart contracts functioned correctly throughout.
Impact
| Affected period | December 6, 2025 – February 7, 2026 |
| Total delegations | 876 |
| Attesters affected | 444 (sent rewards to incorrect split contracts at least once) |
All delegators with a deficit have been fully compensated from our own token allocation. No action was required from any delegator.
Resolution
The bug was identified and fixed on the same day it was discovered (February 7, 2026). Keystores were corrected immediately and all sequencers resumed proposing blocks with the correct coinbase addresses.
We then conducted a full on-chain analysis to calculate the exact deficit for every affected delegator and funded the entire shortfall from our own pre-sale token allocation. Remediation funds were distributed to all affected split contracts at TGE on February 12, 2026.
- All deficit delegators have received their full missing rewards
- No action was required from affected delegators
- No delegator has been or will be asked to return excess tokens
Timeline
| Date | Event |
|---|---|
| Dec 6, 2025 | Bug introduced during internal tooling update to support new validator slots |
| Dec 6 - Feb 7 | A portion of block proposals routed to incorrect split contracts (undetected) |
| Feb 7, 2026 | Bug detected during routine keystore review and fixed same day - all keystores corrected |
| Feb 8, 2026 | Full on-chain impact analysis completed |
| Feb 9, 2026 | Independent verification completed; decision to self-fund the full deficit |
| Feb 12-18, 2026 | Remediation funds distributed to all affected split contracts |
Root cause
Our internal tool that maps delegations to attester keystores relied on array index positions rather than explicit attester identity matching. When the tool was updated on December 6 to support additional validator slots, a sorting change shifted the index mapping, causing coinbase addresses to be assigned to incorrect attesters.
The underlying process - operators manually configuring coinbase addresses in sequencer keystores - is inherently fragile and error-prone at scale. We raised concerns about this design with the Aztec team from our very first delegation. The Aztec team has acknowledged this and is developing a protocol-level fix to automate coinbase assignment, removing the need for manual operator configuration entirely.
What we’ve done to prevent recurrence
- Attester identity verification - The keystore updater now validates that the attester address matches the delegation record before writing any coinbase address. The previous index-based matching pattern has been eliminated.
- Automated real-time monitoring - We have deployed continuous monitoring that compares every keystore coinbase entry against on-chain delegation data, with immediate alerting on any mismatch.
- Dry-run mode with diff review - All keystore modifications now run in dry-run mode first, producing a human-readable diff that must be reviewed and approved before changes are applied to production.
- Pre-deployment validation - Automated consistency checks verify a strict 1:1 attester-to-coinbase mapping before any configuration update takes effect.
Delegator FAQ
Was I affected?
If you delegated to our provider (Provider ID 6) and had an active attester between December 6, 2025 and February 7, 2026, you may have been affected. All deficit delegators have already been compensated - no action is needed on your part.
Do I need to do anything?
No. The remediation has been completed. Your split contract has received the appropriate funds.
What about delegators who received excess rewards?
Some split contracts received more rewards than owed due to the coinbase shift. We covered the full deficit from our own allocation. No delegator will be asked to return tokens.
Will this happen again?
We have implemented automated identity verification, real-time monitoring, and dry-run review processes to make sure this never happens again. Additionally, works is being done on a protocol-level fix that will eliminate the need for manual coinbase configuration entirely.
Who can I contact?
If you have questions about this incident or your specific delegation, please reach out via our Discord channel #aztec-sequencer-support - Join the Nethermind Discord Server!