Answer in brief
CVE-2026-52737 records a Medium severity (CVSS 5.3) vulnerability in ZEBRA: Sync restart poisoning from single unauthenticated peer via above-lookahead block. The current sources do not mark it as known exploited. The current feed maps ZcashFoundation/zebra (generic), ZcashFoundation/zebra-consensus (generic), zebra-consensus (rust), zebrad (rust). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps ZcashFoundation/zebra (generic), ZcashFoundation/zebra-consensus (generic), zebra-consensus (rust), zebrad (rust). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| ZcashFoundation/zebrageneric | < 4.5.0 | Not reported |
| ZcashFoundation/zebra-consensusgeneric | < 7.0.0 | Not reported |
| zebra-consensusrust | <=6.0.0 | 7.0.0 |
| zebradrust | <=4.4.1 | 4.5.0 |
Published upstream
Aug 18, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 9, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 2, 2026
ZEBRA is a Zcash node written entirely in Rust. Prior to 4.5.0, a malicious unauthenticated P2P peer can answer Zebra's outbound getblocks or FindBlocks request with a small two-hash inventory and then serve a syntactically valid block whose coinbase height is far above the local chain tip. In zebrad/src/components/sync/downloads.rs, BlockDownloadVerifyError::AboveLookaheadHeightLimit originally carried only the block height and hash, so handle_block_response could not attribute the failure to the advertising peer. The error then reached the restart-worthy default path in zebrad/src/components/sync.rs, cancelling all in-flight downloads from honest peers and imposing a 67-second sync restart delay on mainnet. Because the peer was neither scored nor disconnected, the peer could repeat the cycle indefinitely with minimal bandwidth and significantly degrade synchronization without corrupting state. This issue is fixed in version 4.5.0.
Quoted source text, attributed separately from HOL analysis.