CVE-2026-67581: Authentication Bypass by Capture-replay in ZenHive mpp allows an unauthenticated remote client to obtain paid

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HIGH 7.5REMOTEUPGRADE

CVE-2026-67581 is a high-severity flaw (CVSS 7.5) affecting machine payments protocol. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Authentication Bypass by Capture-replay in ZenHive mpp allows an unauthenticated remote client to obtain paid resources by resubmitting one settled on-chain transfer. MPP.Methods.EVM.verify/2 accepts a transaction-hash credential and matches a transfer purely on token, to and amount (ERC-20) or to and value (native). It binds the proof neither to the challenge being verified nor to any record of prior use, and the generic MPP.Plug dedup store ke

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 52%)
CISA exploited list	No
Weakness	CWE-294
Published	2026-08-19
Last modified	2026-09-10

Publisher (CNA): EEF · Vendor: zenhive

Last updated 2026-09-10 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-19 18:17 UTCPublished CVE record published
2026-09-10 18:00 UTCUpdated Record last modified

zenhive machine payments protocol UPGRADE

Affected: >= 0.3.0 and < 0.6.4

Fixed in: 0.6.4

Safe to downgrade to: a release before 0.3.0

1. Check installed version

apt-cache policy machine-payments-protocol || rpm -q machine-payments-protocol || machine-payments-protocol --version

2. UPGRADE to 0.6.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade machine-payments-protocol

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade machine-payments-protocol

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 0.3.0 (Debian / Ubuntu)

apt-cache madison machine-payments-protocol sudo apt install machine-payments-protocol=<VERSION_BEFORE_0.3.0> sudo apt-mark hold machine-payments-protocol

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list machine-payments-protocol sudo dnf downgrade machine-payments-protocol-<VERSION_BEFORE_0.3.0> sudo dnf versionlock add machine-payments-protocol

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-2026-67581?

machine payments protocol: upgrade to 0.6.4. Exact commands for each OS are on this page.

Is CVE-2026-67581 being exploited?

CVE-2026-67581 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-2026-67581 affect?

CVE-2026-67581 affects machine payments protocol. Severity is high (CVSS 7.5). Authentication Bypass by Capture-replay in ZenHive mpp allows an unauthenticated remote client to obtain paid resources by resubmitting one settled on-chain transfer. MPP.Methods.EVM.verify/2 accepts a transaction-hash credential and match

How urgent is CVE-2026-67581?

Priority 43/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-73829 LOW 3.7 UPGRADE Time-of-check Time-of-use (TOCTOU) Race Condition in ZenHive mpp allows an unauthenticated remote client to re
CVE-2026-73541 HIGH 8.2 UPGRADE Allocation of Resources Without Limits or Throttling in ZenHive mpp allows an unauthenticated remote client to
CVE-2026-73136 HIGH 7.5 UPGRADE Authentication Bypass by Capture-replay in ZenHive mpp allows an unauthenticated third party to obtain paid re

References

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