EUVD-2026-28801
GHSA-h9hm-m2xj-4rq9
CVSS VectorNVD
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
4DescriptionNVD
ZEBRA is a Zcash node written entirely in Rust. Prior to version 4.4.0, 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. This issue has been patched in version 4.4.0.
AnalysisAI
Remote denial-of-service in Zebra (Zcash node implementation) versions prior to 4.4.0 allows unauthenticated attackers to permanently halt block synchronization via a single TCP connection. The attack exploits three independent weaknesses in gossip, syncer, and download subsystems to create an irreversible block discovery deficit. …
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RemediationAI
Within 24 hours: Audit your environment to identify all Zebra node deployments and document current versions in use. Within 7 days: Upgrade all Zebra instances to version 4.4.0 or later; if immediate upgrade is not feasible, isolate affected nodes from untrusted network segments and implement network ACLs restricting inbound TCP connections to Zebra ports to known trusted peer addresses only. …
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External POC / Exploit Code
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