Read the docs
TI-2026-86699 Aliases CVE-2026-123557GHSA-cpwj-fm29-9h32

Reachable assertion in Zebra zebrad lets remote peers crash nodes

Priority LOW 35CWE-617Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Attack requirements
Present
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-617.

Summary

ZcashFoundation Zebra zebrad before 7.0.0 contains a reachable assertion race condition (CWE-617). An unauthenticated remote peer can abort the node by disconnecting while an outbound send is blocked, which terminates syncing nodes. Malicious peers can trigger this by returning empty FindBlocks or FindHeaders replies and stopping reading from their socket.

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

Description from the CNA

ZcashFoundation Zebra zebrad before 7.0.0 contains a reachable assertion race condition that allows unauthenticated remote peers to abort the node by triggering disconnection during a blocked outbound send. Malicious peers can return empty FindBlocks or FindHeaders replies and stop reading their socket, dropping an unresolved MustUseClientResponseSender and terminating syncing nodes.

Why it matters now

EPSS 0.00308 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
ZcashFoundationzebrabefore 7.0.07.0.0Patch availableCNA
  • zebra VendorZcashFoundation Affected before 7.0.0 Fixed in 7.0.0 Patch available CNA

Remediation

Upgrade zebrad to version 7.0.0, 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-2026-123557
  2. 2026-11-08 Alias added: GHSA-cpwj-fm29-9h32
  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