Polygon Discloses Security Vulnerabilities Fixed by Austin and Kyoto Hard Forks

Polygon disclosed several previously unreported security vulnerabilities that were fixed through two recent hard forks and could have affected its proof-of-stake network. According to Foresight News, the issues involved Polygon's Bor and Heimdall clients and included denial-of-service risks, validator resource exhaustion, and flaws affecting checkpoint and milestone processing.Polygon said the vulnerabilities were patched through the Austin and Kyoto hard forks, with the fixes privately tested before being deployed to mainnet and publicly disclosed. The most serious issue involved Heimdall, where a carefully crafted transaction could force validators to perform excessive processing and disrupt the network. The Austin hard fork also fixed two denial-of-service risks in Bor that could slow block processing or cause nodes to crash. Polygon said the vulnerabilities were not exploited on mainnet and were proactively deployed before details were made public.Polygon Labs previously issued an urgent notice asking node operators to upgrade their clients after the Austin and Kyoto hard forks on Polygon PoS, saying nodes still running pre-fork versions had diverged from canonical consensus.