A soundness vulnerability in the variable-base scalar multiplication gadget of halo2_gadgets allowed a malicious prover to produce a valid proof for an Orchard Action with an under-constrained base point. Because this gadget enforces the diversified-address-integrity condition of the Orchard Action statement, the flaw let a prover satisfy that condition for an arbitrary (pkd, gd, ivk) triple, effectively bypassing the check that binds an Action to the correct incoming viewing key …
The read_getblocks and read_getheaders codec paths accepted block locator vectors up to approximately 65,535 entries (the generic TrustedPreallocate ceiling derived from MAX_PROTOCOL_MESSAGE_LEN), rather than the protocol-specification limit of 101 entries (matching zcashd's MAX_LOCATOR_SZ). Each entry in the locator vector triggers a per-hash chain lookup (HashMap::contains_key + RocksDB::contains_hash) in find_chain_intersection on a tokio blocking-pool thread. A single maximally-sized getblocks message occupies one blocking-pool thread for approximately 10–65ms. Under sustained load from …
The z_listunifiedreceivers RPC handler panics when processing a structurally valid Unified Address whose Sapling receiver carries 43 bytes that fail cryptographic validation (sapling_crypto::PaymentAddress::from_bytes returns None for non-subgroup Jubjub points). The handler calls .expect("using data already decoded as valid") on the fallible result. Because Zebra's release profile sets panic = "abort", the panic terminates the entire node process, not just the RPC task.
The mempool download pipeline's cancel_handles map retains entries for transactions whose verification times out at the outer RATE_LIMIT_DELAY (73-second) boundary. The tokio::time::error::Elapsed error carries no payload, so the transaction ID is unrecoverable and the corresponding cancel_handles entry (including the full Gossip::Tx(UnminedTx), up to ~2 MB) is never removed. Entries accumulate monotonically with no upper bound or garbage collection, leading to eventual out-of-memory process termination.
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.
A single unauthenticated P2P peer can monopolize all 25 inbound mempool download/verification slots (MAX_INBOUND_CONCURRENCY) by advertising fake transaction IDs. While the slots are occupied, all other inbound transactions from honest peers and local RPC sendrawtransaction calls are rejected with MempoolError::FullQueue. The attacker peer is never scored for misbehavior and is not disconnected, allowing sustained denial of mempool admission.
The getblocktemplate RPC handler panics when parsing a LongPollId parameter that contains non-ASCII (multi-byte UTF-8) characters. The handler performs byte-index string slicing on the user-supplied string, which panics in Rust when a byte index falls within a multi-byte character boundary. Because Zebra's release profile sets panic = "abort", the panic terminates the entire node process.
Zebra's P2SH sigop counter uses a pure-Rust code path that short-circuits on disabled opcodes (such as OP_CODESEPARATOR), returning a partial count of zero for any sigops following the disabled opcode. The reference implementation (zcashd) correctly counts through disabled opcodes in its static sigop analysis. This produces a consensus divergence: Zebra accepts blocks that zcashd rejects when the block-wide MAX_BLOCK_SIGOPS = 20,000 threshold is crossed on one side but not the …
Chain::push in the non-finalized state updates the transaction-location index (tx_loc_by_hash) before it runs the duplicate shielded-nullifier guard. When an invalid child block repeats a shielded transaction from its non-finalized parent, the assert_eq!(prior_pair, None, "transactions must be unique within a single chain") fires before the contextual validation that would cleanly reject the duplicate. Under Zebra's panic = "abort" release profile, this terminates the entire node process. The block should be rejected …
The finalized transparent address balance writer processes all newly-created outputs (credits) before processing spent outputs (debits) within the same block. A consensus-valid block containing a long chain of same-address transparent self-spends can cause the intermediate per-address balance during the credit pass to exceed MAX_MONEY, triggering a panic in the finalized state writer. Because the triggering block is consensus-valid (zcashd accepts it), the panic recurs on restart when the node re-encounters …
A malicious peer can answer Zebra's outbound getblocks/FindBlocks request with a small two-hash inventory, then serve a syntactically valid block whose coinbase height is far above the victim's local tip. The AboveLookaheadHeightLimit error in the sync download pipeline triggers a global sync restart rather than being scoped to the offending peer. The peer is never scored or disconnected because the error type does not carry the advertiser address. On mainnet, …
The P2P codec's Codec::decode() method calls src.reserve(body_len + HEADER_LEN) after parsing a 24-byte protocol header, using the attacker-claimed body_len field. This reserves up to MAX_PROTOCOL_MESSAGE_LEN (~2 MiB) of virtual buffer capacity per connection before any body bytes arrive and before the handshake completes. However, BytesMut::reserve() sets virtual capacity without committing physical memory pages. The operating system does not allocate physical RAM until bytes are actually written into the buffer. Since …
Zebra records a block hash in non_finalized_block_write_sent_hashes when the block is sent to the write task, before contextual validation completes. If validation fails, the hash is not removed. A remote unauthenticated peer can deliver a poisoned block body that shares a header hash with a later valid canonical block. The poisoned body is rejected, but the hash remains cached. When the valid canonical block arrives, Zebra treats it as a …
An address normalization mismatch between the handshake path and the mempool misbehavior path causes a deterministic assertion panic when a peer connects via IPv4 to a dual-stack IPv6 listener and then triggers a mempool misbehavior penalty. The handshake path canonicalizes IPv4-mapped IPv6 addresses to plain IPv4 when storing the peer in the address book via MetaAddr::new_connected. The mempool misbehavior path forwards the raw transient socket address (IPv4-mapped IPv6 form) when …
Zebra failed to enforce a ZIP-244 consensus rule for V5 transparent transactions: when an input is signed with SIGHASH_SINGLE and there is no transparent output at the same index as that input, validation must fail. Zebra instead asked the underlying sighash library to compute a digest, and that library produced a digest over an empty output set rather than failing. An attacker could craft a V5 transaction with more transparent …
A composite denial-of-service vulnerability in Zebra's block discovery pipeline allows an unauthenticated remote attacker to permanently halt all new block discovery on a targeted node. The attack exploits three independent weaknesses in the gossip, syncer, and download subsystems — all exercisable from a single TCP connection — to create a monotonically growing block deficit that never self-heals.
For V5+ transparent spends, Zebra and zcashd disagree on the same consensus rule: SIGHASH_SINGLE must fail when the input index has no corresponding output. zcashd treats this as consensus-invalid under ZIP-244, while Zebra's transparent verification path computes a digest for the missing-output case instead of failing. The result is a direct block-validity split. A malformed V5 transparent transaction can be accepted by Zebra, retained in Zebra's mempool, selected into Zebra …
Zebra's block validator undercounts transparent signature operations against the 20000-sigop block limit (MAX_BLOCK_SIGOPS), allowing it to accept blocks that zcashd rejects with bad-blk-sigops. A miner who produces such a block can split the network: Zebra nodes follow the offending chain while zcashd nodes do not. Two distinct undercounts:
Several inbound deserialization paths in Zebra allocated buffers sized against generic transport or block-size ceilings before the tighter protocol or consensus limits were enforced. An unauthenticated or post-handshake peer could therefore force the node to preallocate and parse for orders of magnitude more data than the protocol intended, across headers messages, equihash solutions in block headers, Sapling spend vectors in V5/V4 transactions, and coinbase script bytes in blocks.
The fix for https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-8m29-fpq5-89jj introduced a separate issue due to insuficient error handling of the case where the sighash type is invalid, during sighash computation. Instead of returning an error, the normal flow would resume, and the input sighash buffer would be left untouched. In scenarios where a previous signature validation could leave a valid sighash in the buffer, an invalid hash-type could be incorrectly accepted, which would create a …
A logic error in Zebra's transaction verification cache could allow a malicious miner to induce a consensus split. By carefully submitting a transaction that is valid for height H+1 but invalid for H+2 and then mining that transaction in a block at height H+2, a miner could cause vulnerable Zebra nodes to accept an invalid block, leading to a consensus split from the rest of the Zcash network.
When deserializing addr or addrv2 messages, which contain vectors of addresses, Zebra would fully deserialize them up to a maximum length (over 233,000) that was derived from the 2 MiB message size limit. This is much larger than the actual limit of 1,000 messages from the specification. Zebra would eventually check that limit but, at that point, the memory for the larger vector was already allocated. An attacker could cause …
A vulnerability in Zebra's JSON-RPC HTTP middleware allows an authenticated RPC client to cause a Zebra node to crash by disconnecting before the request body is fully received. The node treats the failure to read the HTTP request body as an unrecoverable error and aborts the process instead of returning an error response.
A vulnerability in Zebra's JSON-RPC HTTP middleware allows an authenticated RPC client to cause a Zebra node to crash by disconnecting before the request body is fully received. The node treats the failure to read the HTTP request body as an unrecoverable error and aborts the process instead of returning an error response.
After a refactoring, Zebra failed to validate a consensus rule that restricted the possible values of sighash hash types for V5 transactions which were enabled in the NU5 network upgrade. Zebra nodes could thus accept and eventually mine a block that would be considered invalid by zcashd nodes, creating a consensus split between Zebra and zcashd nodes. In a similar vein, for V4 transactions, Zebra mistakenly used the "canonical" hash …
After a refactoring, Zebra failed to validate a consensus rule that restricted the possible values of sighash hash types for V5 transactions which were enabled in the NU5 network upgrade. Zebra nodes could thus accept and eventually mine a block that would be considered invalid by zcashd nodes, creating a consensus split between Zebra and zcashd nodes. In a similar vein, for V4 transactions, Zebra mistakenly used the "canonical" hash …
Orchard transactions contain a rk field which is a randomized validating key and also an elliptic curve point. The Zcash specification allows the field to be the identity (a "zero" value), however, the orchard crate which is used to verify Orchard proofs would panic when fed a rk with the identity value. Thus an attacker could send a crafted transaction that would make a Zebra node crash.
Orchard transactions contain a rk field which is a randomized validating key and also an elliptic curve point. The Zcash specification allows the field to be the identity (a "zero" value), however, the orchard crate which is used to verify Orchard proofs would panic when fed a rk with the identity value. Thus an attacker could send a crafted transaction that would make a Zebra node crash.
A logic error in Zebra's transaction verification cache could allow a malicious miner to induce a consensus split. By matching a valid transaction's txid while providing invalid authorization data, a miner could cause vulnerable Zebra nodes to accept an invalid block, leading to a consensus split from the rest of the Zcash network. To be clear, this would not allow invalid transactions to be accepted but could result in a …
A vulnerability in Zebra's transaction processing logic allows a remote, unauthenticated attacker to cause a Zebra node to panic (crash). This is triggered by sending a specially crafted V5 transaction that passes initial deserialization but fails during transaction ID calculation.