According to CoinMeta, researchers disclosed a clock attack targeting older versions of the consensus mechanisms for Proof-of-History ( PoH ) and TowerBFT at the USENIX Security 2026 conference. This attack exploits malicious validators to re-anchor the time state of PoH, extending the valid block generation window and affecting the block proposals of honest validators under certain conditions. Since this attack relies on the old consensus mechanism that will be replaced by the Alpenglow upgrade plan, the security competition rules for 50,000 SOL Alpenglow tokens in Anza may not cover this vulnerability. Researchers stated that the Solana team was informed of this issue in December 2025 and believe that future Alpenglow upgrades will remove the conditions required for this attack, but there is currently no public analysis of the specific implementation of this vulnerability. The study did not prove that this attack has been exploited on the mainnet, nor was any financial loss or compromise to consensus security detected.