Zebra has sync restart poisoning from single unauthenticated peer via above-lookahead block
Zebra has sync restart poisoning from single unauthenticated peer via above-lookahead block. You are affected if: 1. You run zebrad up to and including v4.4.1. 2. Your node accepts inbound P2P connections and is syncing or catching up to the chain tip. 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.
Vuln-watch · relayed from the GitHub Advisory Database; see Source & attribution below
Summary
You are affected if: 1. You run zebrad up to and including v4.4.1. 2. Your node accepts inbound P2P connections and is syncing or catching up to the chain tip. 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.
Affected
- zebra-consensus (rust) <= 6.0.0 — fixed in 7.0.0
- zebrad (rust) <= 4.4.1 — fixed in 4.5.0
Severity
Medium, as rated by the upstream advisory.
Recommended actions
- Upgrade zebra-consensus to 7.0.0 or later
- Upgrade zebrad to 4.5.0 or later
Source & attribution
This 0xCERT advisory summarises GHSA-gvjc-3w7c-92jx / CVE-2026-52737 from the GitHub Advisory Database, credited upstream to ipwning, mpguerra, conradoplg, oxarbitrage: https://github.com/advisories/GHSA-gvjc-3w7c-92jx. Details may change; refer to the original source for the authoritative record.
References
OpenPGP-signed. The signed text of this advisory verifies against the 0xCERT key CCC7 D9EC 9415 723D.
Published 2026-07-02 · last updated 2026-10-08
curl -s https://www.0xcert.com/pgp.asc | gpg --import && curl -s https://www.0xcert.com/advisory/0xCERT-2026-0206/signed.txt | gpg --verify