CVE-2026-40583

// Conceptual Proof of Concept for CVE-2026-40583 // This demonstrates the vulnerable logic flow in UltraDAG v0.1 struct Transaction { sender: String, signature: Vec<u8>, nonce: u64, payload: Payload, } enum Payload { Vote { candidate: String }, } struct State { votes: HashMap<String, u64>, } // Simulating the vulnerable function fn process_transaction_vulnerable(tx: &Transaction, state: &mut State) -> Result<(), String> { // Step 1: Prechecks (Signature, Nonce, Balance) // Attacker passes these easily with a valid account if !verify_signature(&tx) { return Err("Invalid Signature".to_string()); } if !check_nonce(&tx) { return Err("Invalid Nonce".to_string()); } // VULNERABILITY: State mutation happens BEFORE authorization check // The system applies the vote to the state if let Payload::Vote { candidate } = &tx.payload { *state.votes.entry(candidate.clone()).or_insert(0) += 1; println!("State mutated: Vote recorded for {}", candidate); } // Step 2: Authorization Check // This check happens too late. Even if it fails, state is already changed. if !is_council_member(&tx.sender) { // In the vulnerable version, this error might be returned, // but the state mutation above is not rolled back effectively. return Err("Authorization Failed: Sender is not a council member".to_string()); } Ok(()) } // Helper stubs fn verify_signature(_tx: &Transaction) -> bool { true } fn check_nonce(_tx: &Transaction) -> bool { true } fn is_council_member(sender: &str) -> bool { // Attacker is not in the council sender != "attacker" }

{"cve": {"id": "CVE-2026-40583", "sourceIdentifier": "[email protected]", "published": "2026-04-21T17:16:56.083", "lastModified": "2026-04-27T15:23:05.487", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "UltraDAG is a minimal DAG-BFT blockchain in Rust. In version 0.1, a non-council attacker can submit a signed SmartOp::Vote transaction that passes signature, nonce, and balance prechecks, but fails authorization only after state mutation has already occurred."}], "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:L/VA:H/SC:N/SI:N/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:Red", "baseScore": 8.8, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "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": "RED"}}], "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:L/A:H", "baseScore": 8.2, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 4.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-460"}, {"lang": "en", "value": "CWE-696"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:ultradag:ultradag:0.1.0:*:*:*:*:*:*:*", "matchCriteriaId": "52EB5FF9-89C8-463E-AFF6-97F273F25877"}]}]}], "references": [{"url": "https://github.com/UltraDAGcom/core/commit/2f5a3a237ea519b48d71e6e3093c89f60694c7be", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/UltraDAGcom/core/commit/45bcf7064741897319b6196d3d9f9e1307093511", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/UltraDAGcom/core/security/advisories/GHSA-q8wx-2crx-c7pp", "source": "[email protected]", "tags": ["Exploit", "Mitigation", "Vendor Advisory"]}, {"url": "https://github.com/UltraDAGcom/core/security/advisories/GHSA-q8wx-2crx-c7pp", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Mitigation", "Vendor Advisory"]}]}}