Polygon Discloses Fixed Security Vulnerabilities in the Austin and Kyoto Hard Forks

ChainCatcher report: Polygon has disclosed multiple previously undisclosed security vulnerabilities recently patched through the Austin and Kyoto hard forks, which could affect its proof-of-stake network. The vulnerabilities involve Polygon’s Bor and Heimdall clients, including risks of denial-of-service, validator resource exhaustion, and flaws impacting checkpoint and milestone processing. Polygon stated that the fixes were privately tested before deployment to mainnet and public disclosure. The most severe issue resides in Heimdall, where specially crafted transactions could force validators to perform excessive processing, disrupting the network. The Austin hard fork also patched two denial-of-service vulnerabilities in Bor that could slow block processing or cause node crashes. Polygon confirmed that these vulnerabilities were not exploited on mainnet and that the fixes were proactively implemented prior to public disclosure of the details.