Polygon discloses vulnerability details: multiple undisclosed security vulnerabilities have been patched.

Polygon has disclosed multiple previously unreported security vulnerabilities fixed via two recent hard forks—Austin and Kyoto—that could impact its Proof-of-Stake network. The flaws involve Polygon’s Bor and Heimdall clients, including denial-of-service (DoS) risks, validator resource exhaustion, and defects affecting checkpoint and milestone processing. Polygon said the fixes were completed in private testing before being deployed to the mainnet and publicly revealed. The most severe issue relates to Heimdall: a carefully crafted transaction could force validators to perform excessive processing, disrupting the network. The Austin hard fork also fixed two DoS risks in Bor, which could slow block processing or cause node crashes. Polygon noted that these vulnerabilities were not exploited on the mainnet, and the repairs were completed proactively before details of the flaws were made public.