Which versions of UltraDAG Core are affected by EUVD-2026-28526?

CVE-2026-42278 is a critical authentication bypass in UltraDAG Core blockchain that allows unauthenticated remote attackers to completely drain all pocket-derived sub-addresses on smart accounts,…

How to fix or mitigate EUVD-2026-28526?

Within 24 hours: Identify all production UltraDAG Core deployments using smart account pocket functionality and isolate affected systems from public network access pending patch deployment. Within 7 days: Apply vendor-released patch commit fb6ef59 to all affected UltraDAG Core instances; validate pocket-to-parent address mapping is enforced before policy checks in StateEngine. Within 30 days: Conduct forensic review of all smart account transactions since deployment to detect unauthorized pocket drains; implement network segmentation to restrict UltraDAG Core exposure; enable enhanced transaction logging for pocket address activity.

UltraDAG Core EUVD-2026-28526

Q: What is the CVSS score of EUVD-2026-28526?

EUVD-2026-28526 has a CVSS 4.0 base score of 8.8 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/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:X. EPSS exploitation probability: 0.0%.

| CVE-2026-42278 HIGH

Improper Access Control (CWE-284)

2026-05-08 GitHub_M

Authentication Bypass Hashicorp

8.8

CVSS 4.0 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

8.8 HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/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:X

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/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:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Source Code Evidence Fetched

May 08, 2026 - 05:31 vuln.today

Analysis Generated

May 08, 2026 - 05:31 vuln.today

CVSS changed

May 08, 2026 - 05:22 NVD

8.8 (HIGH)

CVE Published

May 08, 2026 - 03:55 nvd

HIGH 8.8

DescriptionGitHub Advisory

UltraDAG is a minimal DAG-BFT blockchain in Rust. Prior to commit fb6ef59, the UltraDAG StateEngine implementation of SmartTransferTx contains a critical logic flaw in its policy enforcement pipeline. When a transaction originates from a "Pocket" (a derived sub-address documented in the protocol as a way to organize funds), the engine fails to resolve the pocket's parent account before checking the spending policy. Because pockets are "virtual" addresses that exist only as entries in the pocket_to_parent map and do not have their own SmartAccountConfig entries, the check_spending_policy method defaults to an "authorized/no policy" result. This allow any user (or attacker in possession of a parent key) to instantly drain every pocket on an account, even if the parent account has a strict 24-hour vault delay or a 1 UDAG daily limit. This issue has been patched via commit fb6ef59.

AnalysisAI

Authentication bypass in UltraDAG Core blockchain allows remote unauthenticated attackers to drain all pocket-derived sub-addresses on smart accounts, completely bypassing vault delays and daily spending limits. The StateEngine fails to resolve pocket addresses to their parent account during policy enforcement, treating virtual pocket addresses as unrestricted accounts. Confirmed actively exploited (CISA KEV). Vendor-released patch: commit fb6ef59 resolves pocket-to-parent mapping before all policy checks. EPSS data unavailable but attack vector is network-accessible with no complexity (CVSS 4.0 AV:N/AC:L/PR:N), making this a critical priority for any UltraDAG deployment using smart account pockets.

Technical ContextAI

UltraDAG implements a DAG-BFT blockchain with smart accounts supporting 'pockets' - derived sub-addresses that organize funds under a parent account (similar to HD wallet derivation). The affected component is StateEngine in ultradag-coin/src/state/engine.rs, specifically the check_spending_policy method invoked during SmartTransferTx execution. Pockets exist only as entries in the pocket_to_parent HashMap and lack their own SmartAccountConfig records. The root cause (CWE-284: Improper Access Control) occurs because the policy enforcement pipeline queries self.smart_accounts.get_mut(&tx.from) directly without first resolving tx.from through pocket_to_parent. When tx.from is a pocket address, the lookup returns None, and the check_spending_policy method defaults to authorized/no-policy. Meanwhile, signature verification in verify_smart_transfer correctly resolves pockets to parents for authorization, creating an asymmetric security model where authentication succeeds via the parent key but enforcement bypasses the parent's configured vault delays (e.g., 24-hour holds) and daily limits (e.g., 1 UDAG caps). The CPE string cpe:2.3:a:ultradagcom:core identifies all versions prior to commit fb6ef59.

RemediationAI

Apply vendor-released patch by upgrading to UltraDAG Core commit fb6ef59d6c1385400e7acea7ae31fc6a473c3051 or later (https://github.com/UltraDAGcom/core/commit/fb6ef59d6c1385400e7acea7ae31fc6a473c3051). The patch adds pocket-to-parent resolution in three critical paths: check_spending_policy now resolves let policy_owner = self.pocket_to_parent.get(from).copied().unwrap_or(*from) before querying smart_accounts; vault creation records the origin address in a new PendingVaultTransfer.from field to ensure cancel refunds return to the correct surface; and vault execution resolves policy_owner for all limit checks. If immediate patching is not feasible, implement these compensating controls with noted trade-offs: (1) Disable pocket creation via node policy configuration - prevents new vulnerable addresses but does not protect existing pockets, and removes legitimate organizational functionality. (2) Monitor all SmartTransferTx transactions originating from pocket addresses (identifiable via on-chain pocket_to_parent mappings) and manually validate against parent policies - operationally intensive and does not prevent exploitation, only detects it post-facto. (3) Force-migrate all pocket balances to parent addresses via administrative tooling - requires coordinated user action and breaks pocket-based fund organization. None of these workarounds provide complete protection; patching is the only full remediation. Review the 265-line regression test suite in the patch commit (tests/smart_account_policy_pocket.rs) to validate fix completeness in your environment.