ZEBRA-STATE · CVE-2026-52733 · Package
FIX → 7.0.0 · 4.5.0
After a chain fork, zebrad keeps stale Sapling and Orchard subtree root data and writes it to its RocksDB state database when the new chain finalizes. Wallet-sync data served by z_getsubtreesbyindex, used by lightwalletd, can then be wrong and survives restarts.
first public May 29, 2026 · 2 sources
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Operators of zebrad nodes at or below 4.4.1 on any Zcash network with forks, including default configurations, are affected, since the stale data is written on finalization after any fork. Systems that depend on z_getsubtreesbyindex, mainly lightwalletd and light wallets, are the ones that show wrong results. Nodes that never run zebrad, or that already run 4.5.0 or later, can skip it. The advisory notes that a state rebuild is needed to clear existing corruption.
Not affected if no-zebrad, zebrad-4.5.0-or-later
Who cares lightwalletd, rocksdb, zcash, zebra-state, zebrad
zebrad --version; versions up to and including 4.4.1 are affected per the advisory.6.0.0 are affected.z_getsubtreesbyindex output against a known-good reference node, as the advisory suggests.You are affected if:
zebrad up to and including v4.4.1.All default configurations are affected. The corruption persists across restarts because it is written to RocksDB.
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.
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.
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Upgrade to 7.0.0 · 4.5.0
4.5.07.0.0When 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.
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.
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 consistency using z_getsubtreesbyindex against a known-good reference.
Persistent corruption of Sapling and Orchard subtree root history in the RocksDB state database. The corruption survives node restarts. Downstream consumers that rely on z_getsubtreesbyindex for wallet synchronization (primarily lightwalletd and light wallets) receive incorrect subtree roots. This does not directly affect consensus validation of new blocks but can cause wallet synchronization failures or incorrect wallet state. Recovery requires rebuilding the state database from scratch.
Reported by @dingledropper via a private GitHub Security Advisory submission.
This page as .md · .json · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L
GitHub Advisory Database, CC-BY 4.0 · NVD data is provided by NIST and is public domain. Posts quoted belong to their authors.