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TI-2026-32433 Aliases CVE-2026-44499GHSA-h9hm-m2xj-4rq9

ZEBRA: Permanent Block Discovery Halt via Gossip Queue Saturation and Syncer Poisoning

Priority MEDIUM 44CWE-770Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-770.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00351 28th percentileScored 2026-11-07
Fix Fixed zebra (ZcashFoundation): 4.4.0zebrad (crates.io): 4.4.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
ZcashFoundationzebrabefore 4.4.04.4.0Patch availableCNA
—zebrad (crates.io)before 4.4.04.4.0Patch availableGHSA-h9hm-m2xj-4rq9
  • zebra VendorZcashFoundation Affected before 4.4.0 Fixed in 4.4.0 Patch available CNA
  • zebrad (crates.io) Vendor— Affected before 4.4.0 Fixed in 4.4.0 Patch available GHSA-h9hm-m2xj-4rq9

Remediation

  • Fix · CNA zebra (ZcashFoundation) Fixed in 4.4.0
  • Fix · GHSA-h9hm-m2xj-4rq9 zebrad (crates.io) Fixed in 4.4.0 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-44499
  2. 2026-10-03 Alias added: GHSA-h9hm-m2xj-4rq9

References

Advisory 1

Other 2

  • TI-2026-66079 Zebra before 4.4.0 Consensus Split via SIGHASH_SINGLE Missing-Output Handling CVSS 4.0HIGH 8.3
  • TI-2026-37850 ZEBRA: Mempool transaction admission denial via single-peer inbound queue saturation CVSS 3.1MEDIUM 5.3
  • TI-2026-71182 Improper block validation in Zebra gossip lets peers drop new blocks CVSS 4.0MEDIUM 6.3
  • TI-2026-29537 Zebra: addr/addrv2 Deserialization Resource Exhaustion CVSS 4.0MEDIUM 6.3
  • TI-2026-86702 Incomplete cleanup in Zebra lets peers stall initial sync CVSS 4.0HIGH 8.7
  • TI-2026-86701 Quadratic signature hashing in Zcash Zebra enables denial of service CVSS 4.0HIGH 8.7
See all 51 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences