CVE-2026-34377

ZEBRA, a Zcash node written in Rust, before version 4.5.0 can accept a block that zcashd rejects due to undercounting the P2SH signature-operation counter for scripts containing a disabled opcode. An attacker can exploit this to cause a chain split, affecting network integrity and availability.

ZEBRA (Zcash node) before version 4.5.0 has a vulnerability allowing an unauthenticated IPv4 peer to deterministically terminate a synced node. By completing a P2P handshake and advertising an invalid mempool transaction, the attacker can trigger an assertion in the code, causing a panic/abort that stops the node. The issue is fixed in version 4.5.0.

ZEBRA prior to 4.5.0 can be terminated by a malicious block producer by placing the same shielded transaction in a non-finalized parent block and its child. The uniqueness assertion is reachable before contextual validation, and release builds use panic=abort, terminating the process.

ZEBRA prior to 4.5.0 can be permanently halted by a consensus-valid block containing a long chain of transparent self-spends. The credit-first ordering can cause the intermediate balance to exceed MAX_MONEY, leading to a panic in release builds. The block is accepted by zcashd, so the halt persists after restart.

ZEBRA prior to 4.5.0 can be slowed down by a malicious P2P peer that answers getblocks/FindBlocks with a small inventory and serves a block with coinbase height far above the local tip. The error is not attributed to the peer, causing cancellation of downloads and a 67-second sync delay. The peer is not scored or disconnected, so it can repeat the attack.

ZEBRA before version 4.5.0 has a vulnerability allowing a remote unauthenticated P2P peer to stall a node by racing an invalid block body against the valid canonical body for the same block header hash. This causes the node to reject the valid body and remain stuck one height behind until restart or reorganization. The issue is fixed in version 4.5.0.

ZEBRA is a Zcash node written in Rust. Prior to 4.5.0, an unauthenticated P2P peer can cause the mempool download pipeline to retain transactions after the RATE_LIMIT_DELAY timeout. This leads to unbounded memory growth and potential node crash.

ZEBRA is a Zcash node written in Rust. Prior to 4.5.0, a chain fork can leave stale Sapling and Orchard note-commitment subtree roots in Zebra state. This can lead to incorrect subtree roots served to consumers like lightwalletd, causing wallet sync failures.

ZEBRA is a Zcash node written in Rust. Prior to 4.5.0, one unauthenticated P2P peer can monopolize all 25 MAX_INBOUND_CONCURRENCY slots in the inbound mempool download pipeline. This can cause honest transactions to be rejected with MempoolError::FullQueue.

ZEBRA is a Zcash node written in Rust. Prior to 4.5.0, an attacker authenticated to an enabled RPC endpoint can terminate zebrad by supplying a getblocktemplate LongPollId with multi-byte UTF-8 characters. This triggers a Rust panic, and release builds use panic=abort, killing the process.