UltraDAG: Smart Account Spending Policy Bypass via Pockets

published 2026-05-08 6 mo ago modified 2026-10-26 13 d ago also EUVD-2026-28526

cvss: 8.8; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 39%
public exploits: 0; none known

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.

Patch / fix

links 1

github.com/UltraDAGcom/core@fb6ef59 commit

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: total
Assessed: 6 mo ago (2026-05-08)

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/UltraDAGcom/core/security/advisories/GHSA-9chc-gjfr-6hrq referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.8	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
CNA	4.0	8.8	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

Affected products

UltraDAGcom core

Classification

Weakness

CWE-284 Improper Access Control
CWE-639 Authorization Bypass Through User-Controlled Key

References

Sources

CVE List CVE-2026-42278
NVD CVE-2026-42278

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary