
Polygon Bug Forces Emergency Hard Fork to Restore Finality
Summary
On September 10, 2025, the Polygon blockchain (Layer‑2 network on Ethereum) experienced a serious bug that delayed transaction finality by 10 to 15 minutes. To remediate, the Polygon Foundation deployed an emergency hard fork. This fixed the issue, and normal operations resumed shortly afterward. icobench.com
Details
What Happened: Finality Delay
Polygon’s network backbone—its mainnet—continued producing blocks and checkpoints, but transactions were not being finalized in the usual timeframe. Validators had difficulty confirming milestones, and there was a risk of reorganization (rollback) of the network state. icobench.com
Ethereum (which is the underlying chain for Polygon’s L2) continued operating normally. The problem was localized to Polygon’s validation/finality process. icobench.com
The Hard Fork Fix
The Foundation identified a fix and rolled it out to all validators. icobench.com
Two of Polygon’s internal protocols were upgraded:
Bor (responsible for block production) was updated to version Bor v2.2.11‑beta2. icobench.com
Heimdall (responsible for consensus, validation, coordination) was updated to version Heimdall‑v2 v0.3.1. icobench.com
Impact & Aftereffects
After the hard fork, finality, state sync, and checkpoint processing returned to normal. icobench.com
Price of the native token POL dropped slightly amid the issue (from about $0.2717 to $0.2668), but recovered to $0.2718 when resolution was confirmed. icobench.com
The bug raised concerns about network reliability and integrity, especially given past incidents of finality delays in 2020. icobench.com
Significance
Finality delays of this kind can undermine confidence in blockchain networks, especially Layer‑2s meant to improve speed and scalability. This incident showed the risk that bugs in validation/finality layers pose.
Quick detection + response by the Polygon Foundation was crucial to limiting damage. The hard fork demonstrates that emergency protocol upgrades remain an important tool for blockchain maintenance.
Token market behavior suggests that even technical faults which are resolved quickly can temporarily affect investor sentiment, but recovery is possible if communication is transparent and fixes are effective.