# CVE-2026-42278: UltraDAG: Smart Account Spending Policy Bypass via Pockets

> Attackers can bypass spending policies and drain funds from derived pockets in UltraDAG by exploiting a logic flaw in transaction validation.

- **Severity:** High 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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 8 May 2026
- **Updated:** 8 May 2026
- **Also known as:** GHSA-9chc-gjfr-6hrq

## What is CVE-2026-42278?

CVE-2026-42278 is a high-severity vulnerability in UltraDAGcom core, published on 8 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key), CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2026-42278?


## How do I fix CVE-2026-42278?

No fix has been published for CVE-2026-42278 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-42278 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42278 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42278 and fix it if it is affected.

What it is: CVE-2026-42278 is a high-severity vulnerability in UltraDAGcom core, published on 8 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42278 exists.

Affected product: UltraDAGcom core. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-42278/ (Markdown: https://insights.sbomify.com/CVE-2026-42278/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42278
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42278
- OSV: https://osv.dev/vulnerability/CVE-2026-42278

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42278/
Summaries are generated and may contain mistakes; the official description above is the record.