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.
History

Sat, 09 May 2026 00:00:00 +0000

Type Values Removed Values Added
First Time appeared Zcashfoundation
Zcashfoundation zebra
Vendors & Products Zcashfoundation
Zcashfoundation zebra

Fri, 08 May 2026 18:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 08 May 2026 16:00:00 +0000

Type Values Removed Values Added
Description 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.
Title ZEBRA: Permanent Block Discovery Halt via Gossip Queue Saturation and Syncer Poisoning
Weaknesses CWE-770
References
Metrics cvssV4_0

{'score': 8.7, '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'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-08T17:23:27.910Z

Reserved: 2026-05-06T18:28:20.886Z

Link: CVE-2026-44499

cve-icon Vulnrichment

Updated: 2026-05-08T17:23:24.967Z

cve-icon NVD

Status : Deferred

Published: 2026-05-08T16:16:13.117

Modified: 2026-05-12T16:45:18.893

Link: CVE-2026-44499

cve-icon Redhat

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