Security Fixes and a Lower Fee Standard The @ZcashFoundation has released Zebra 6.4.0 and 6.4.1, its latest updates to the Zebra node software. Node operators are strongly encouraged to upgra
The @ZcashFoundation has released Zebra 6.4.0 and 6.4.1, its latest updates to the Zebra node software. Node operators are strongly encouraged to upgrade straight to version 6.4.1.
One of the patched vulnerabilities allowed a peer to serve a block with a valid canonical hash but a forged body whose authorizing data did not match the header commitment. Zebra previously treated this as an ordinary invalid block, causing it to cancel the sync round and drop the block hash entirely, which could allow a malicious actor to stall syncing.
Both releases also lower the standard transaction fee. The mempool now accepts transactions that pay at least 1,000 zatoshis per ZIP-317 logical action, down from the previous 5,000. That translates to a fee of 0.00001 $ZEC per action.
The update carries an important timing change for node runners. The end-of-support window has been shortened from 15 weeks to 12 weeks, meaning Zebra 6.4.x will halt around November 2, just ahead of NU7's tentative November 5 activation. The Foundation acknowledged the shortened window is not ideal but said it is necessary to ensure nodes move to the NU7-supporting release in time. Operators can check their exact halt height and estimated time using the getdeprecationinfo RPC.
The pressure to upgrade is tied directly to what NU7 brings. Zcash developers are targeting November 5 for NU7, which would cut block times from 75 seconds to 25 seconds, making private payments up to three times faster. NU7 would also temporarily remove about 60% of transaction fees from circulation, with those funds scheduled to return as mining rewards from February 2031, while preserving Zcash's issuance and halving schedule. The final mainnet activation decision is due October 20, after NU7 reaches Zcash's test network on October 6.
For now, the immediate priority is clear. Node operators running Zebra must upgrade to version 6.4.1 and prepare for a further update, expected in the coming week, that will include full NU7 support before the early November halt.
Sources:Zcash Foundation: Zebra 6.4.0 and 6.4.1 Release NotesZebra v6.4.0 GitHub ReleaseCoinDesk: Zcash Targets November Upgrade
