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TI-2026-86696 Aliases CVE-2026-123554GHSA-5872-wrc4-qh77

Denial of service in Zebra zebrad via mempool coinbase-maturity check

Priority LOW 38CWE-407Published · 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. Impact type from CWE-407.

Summary

Zebra zebrad from 6.4.0 before 7.0.0 performs quadratic work in the mempool coinbase-maturity check because the transaction's output list is rebuilt once per spent outpoint. Any connected peer can send repeated unsigned transactions with many transparent inputs and outputs, which are rejected without a misbehavior score, tying up verification threads. An unauthenticated remote attacker can cause a denial of service, as the flaw is classified as CWE-407.

Written with Claude Haiku 5.5 from the sources below · 2026-11-08

Description from the CNA

Zebra zebrad 6.4.0 before 7.0.0 performs quadratic work in the mempool coinbase-maturity check because Transaction::coinbase_spend_restriction() rebuilds the transaction's output list once per spent outpoint. Any connected peer can repeatedly send unsigned transactions with many transparent inputs and outputs, which are rejected without a misbehavior score, to pin verification threads.

Why it matters now

EPSS 0.00432 37th percentileScored 2026-11-08
Fix Fixed zebra (ZcashFoundation): 7.0.0

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
ZcashFoundationzebra6.4.0 to before 7.0.07.0.0Patch availableCNA
  • zebra VendorZcashFoundation Affected 6.4.0 to before 7.0.0 Fixed in 7.0.0 Patch available CNA

Remediation

Upgrade ZcashFoundation zebra to version 7.0.0 or later, which fixes the issue.

Written with Claude Haiku 5.5 from the sources below · 2026-11-08

  • Fix · CNA zebra (ZcashFoundation) Fixed in 7.0.0

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    ZcashFoundation zebra 7.0.0

    7 records Highest priority Priority LOW 7 LOW

    Other records, highest priority first

    • TI-2026-86702 Incomplete cleanup in Zebra lets peers stall initial syncPriority LOW 38
    • TI-2026-86701 Quadratic signature hashing in Zcash Zebra enables denial of servicePriority LOW 38
    • TI-2026-86700 Improper cleanup stalls Zebra checkpoint sync via a malicious peerPriority LOW 38
    Show all 7 records →

Timeline

  1. 2026-11-08 Threatist record created from CVE-2026-123554
  2. 2026-11-08 Alias added: GHSA-5872-wrc4-qh77
  3. 2026-11-09 Priority changed: MEDIUM → LOW

References

Patch 1

Advisory 1

  • 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-2026-30136 ZEBRA: Consensus Divergence in Transparent Sighash Hash-Type Handling CVSS 4.0CRITICAL 9.3
  • TI-2026-37853 ZEBRA: Consensus divergence via P2SH sigop undercount in pure-Rust disabled-opcode parser CVSS 4.0CRITICAL 9.3
See all 51 →

Sources

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