CVE-2026-44499 HIGH

CVE-2026-44499: ZEBRA: Permanent Block Discovery Halt via Gossip Queue Saturation and Syncer Poisoning

Vendor Zcashfoundation
Product zebra
Weakness CWE-770 · Uncontrolled resource consumption
Published May 8, 2026
Last update May 8, 2026

CVSS base score

8.7/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS vector

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

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

May 8, 2026 CVE published
May 8, 2026 Record updated