Read the docs
TI-2026-66067 Aliases CVE-2026-104424GHSA-3xx8-299f-8q53

Zebra before 6.1.0 Incorrect Block Size Calculation in getblocktemplate

Priority LOW 28CWE-131Published · Updated

Key facts

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

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

Summary

Zebra before 6.1.0 contains an incorrect calculation vulnerability in its ZIP-317 block template selector that omits header and transaction-count size from the block budget. Attackers can place valid selectable transactions in a victim miner's mempool to shape templates into oversized blocks, causing rejection and wasted proof-of-work.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00273 19th percentileScored 2026-11-07
Fix Fixed zebra (ZcashFoundation): 6.1.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
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 6.1.06.1.0Patch availableCNA
  • zebra VendorZcashFoundation Affected before 6.1.0 Fixed in 6.1.0 Patch available CNA

Remediation

  • Fix · CNA zebra (ZcashFoundation) Fixed in 6.1.0

Fixed in the same release

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

  • Release ·

    ZcashFoundation zebra 6.1.0

    4 records Highest priority Priority LOW 4 LOW

    Other records, highest priority first

    • TI-2026-66068 Zebra before 6.1.0 Batch-Verification Poisoning DoS via Unattributed Pushed TransactionsPriority LOW 36
    • TI-2026-66070 Zebra before 6.1.0 Chain Stall via Stale parent_error_map EntryPriority LOW 35
    • TI-2026-66069 Zebra before 6.1.0 Quadratic Complexity DoS via Block Transparent Value CheckPriority LOW 35
    Show all 4 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-104424
  2. 2026-10-03 Alias added: GHSA-3xx8-299f-8q53
  3. 2026-10-04 Priority changed: MEDIUM → LOW
  4. 2026-10-06 CISA SSVC decision points changed

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

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