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TI-2026-66073 Aliases CVE-2026-104430GHSA-4c53-mmm8-cf87

Zebra 4.5.0 Consensus Split via P2SH Sigop Overcount

Priority MEDIUM 44CWE-628Published · Updated

Key facts

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

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

Zebra zebrad 4.5.0 and zebra-script 7.0.0 count P2SH redeem script signature operations in legacy mode rather than zcashd's accurate P2SH mode, overcounting CHECKMULTISIG preceded by OP_1 through OP_16 as 20 sigops and causing a consensus divergence. Remote attackers can broadcast P2SH spends using low-threshold multisig redeem scripts so that a block zcashd accepts exceeds Zebra's inflated MAX_BLOCK_SIGOPS count, causing Zebra nodes to reject it and stall off the chain.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00409 35th percentileScored 2026-11-07
Fix Fixed zebra (ZcashFoundation): 4.5.1, 7.0.1

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
ZcashFoundationzebra4.5.0 to before 4.5.14.5.1Patch availableCNA
ZcashFoundationzebra7.0.0 to before 7.0.17.0.1Patch availableCNA
  • zebra VendorZcashFoundation Affected 4.5.0 to before 4.5.1 Fixed in 4.5.1 Patch available CNA
  • zebra VendorZcashFoundation Affected 7.0.0 to before 7.0.1 Fixed in 7.0.1 Patch available CNA

Remediation

  • Fix · CNA zebra (ZcashFoundation) Fixed in 4.5.1
  • Fix · CNA zebra (ZcashFoundation) Fixed in 7.0.1

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-104430
  2. 2026-10-03 Alias added: GHSA-4c53-mmm8-cf87

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 44 →

Sources

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