CVE-2026-104424

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.

  • Published Oct 2, 2026
  • CVSS 6.3 medium
  • 0.3% chance of exploitation in the next 30 days (EPSS)
  • A fix is available

Affected software

CVE-2026-104424 at the National Vulnerability Database