high8.7
CVE-2026-44499
Zebra has Permanent Block Discovery Halt via Gossip Queue Saturation and Syncer Poisoning
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| rust | zebrad | < 4.4.0 | 4.4.0 |