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TI-2026-86698 Aliases CVE-2026-123556GHSA-7gc8-jc34-45g3

Honest peer ban in Zcash Zebra via mempool lock-time scoring

Priority LOW 30CWE-693Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
None · None · Low
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-693.

Summary

ZcashFoundation Zebra from 4.5.0 before 7.0.0 has a protection mechanism failure (CWE-693). Mempool lock-time rejections are scored at the ban threshold, so a remote attacker can broadcast transactions locked until the current height right after each block. Lagging nodes then ban honest relaying peers for 24 hours or until restart.

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

Description from the CNA

ZcashFoundation Zebra from 4.5.0 before 7.0.0 contains a protection mechanism failure that bans honest peers by scoring mempool lock-time rejections at the ban threshold. Attackers can broadcast transactions locked until the current height right after each block, causing lagging nodes to ban honest relaying peers for 24 hours or until restart.

Why it matters now

EPSS 0.00304 23rd 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
ZcashFoundationzebra4.5.0 to before 7.0.07.0.0Patch availableCNA
  • zebra VendorZcashFoundation Affected 4.5.0 to before 7.0.0 Fixed in 7.0.0 Patch available CNA

Remediation

Upgrade ZcashFoundation Zebra to version 7.0.0.

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-2026-123556
  2. 2026-11-08 Alias added: GHSA-7gc8-jc34-45g3
  3. 2026-11-09 Priority changed: MEDIUM → LOW

References

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