CVE-2026-40583: UltraDAG is a minimal DAG-BFT blockchain in Rust

This week

HIGH 8.2REMOTEDOWNGRADE

CVE-2026-40583 is a high-severity flaw (CVSS 8.2) affecting ultradag. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	8.2 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 69%)
CISA exploited list	No
Weakness	CWE-460, CWE-696
Published	2026-04-21
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: ultradag

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-21 17:16 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

ultradag ultradag DOWNGRADE

Affected: 0.1.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.1.0

1. Check installed version

apt-cache policy ultradag || rpm -q ultradag || ultradag --version

2. No fixed release: DOWNGRADE to a release before 0.1.0 (Debian / Ubuntu)

apt-cache madison ultradag sudo apt install ultradag=<VERSION_BEFORE_0.1.0> sudo apt-mark hold ultradag

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list ultradag sudo dnf downgrade ultradag-<VERSION_BEFORE_0.1.0> sudo dnf versionlock add ultradag

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-40583?

ultradag: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-40583 being exploited?

CVE-2026-40583 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-40583 affect?

CVE-2026-40583 affects ultradag. Severity is high (CVSS 8.2). 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 ha

How urgent is CVE-2026-40583?

Priority 47/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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