CVE-2026-52733

Am I affected You are affected if: 1. You run zebrad up to and including v4.4.1. 2. Your node participates in a network where chain forks occur (mainnet, testnet, or any network with multiple miners). All default configurations are affected. The corruption persists across restarts because it is written to RocksDB. Summary When pop_tip removes the tip block during a chain fork, stale Sapling and Orchard note commitment subtree root data is retained in the in-memory non-finalized state. When the chain subsequently finalizes, this stale data is written to the persistent RocksDB state. The corrupted subtree root history affects z_getsubtreesbyindex (used by lightwalletd for wallet synchronization) and could affect future chain verification that depends on correct subtree roots. Details The non-finalized state provides two methods for removing blocks: pop_root (removes the oldest block during finalization) and pop_tip (removes the newest block during a fork revert). pop_root correctly cleans up note commitment subtree contributions. pop_tip does not: it removes the block but retains the block's subtree root contributions in the in-memory state. When a chain fork occurs and pop_tip reverts the old tip, the winning fork's chain is extended. When that chain is later finalized, the stale subtree data from the reverted blocks is included in the RocksDB write batch and persisted to disk. The pop_root/pop_tip asymmetry is specific to subtree root handling. Other state managed by pop_tip (nullifiers, UTXOs, anchors, block hashes) uses different cleanup patterns that are not affected. Patches zebra-state 7.0.0 and zebrad 4.5.0. The fix adds subtree root cleanup to pop_tip matching the pattern already used by pop_root. Workarounds There is no configuration-level workaround. Chain forks are natural events on any Proof-of-Work network. Operators can mitigate the downstream impact by periodically verifying subtree root con

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