[ CVE-2026-104421 · Published 2 Oct 2026 ]
Vulnerability in ZcashFoundation zebra
CVSS 5.3
EPSS <1%No fix listed yet
[ Description ]Official description
Zebra before 6.2.1 contains an incomplete cleanup vulnerability that allows unauthenticated peers to block downloading of valid blocks by leaving rejected hashes in SentHashes. Attackers can send a contextually invalid block sharing an honest block's header hash, causing Request::KnownBlock to skip the honest block and keep nodes behind the tip.
[ Fixes ]Fixes and patches
No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.