CVE-2026-34209Network attack vector

Unauthenticated channel closure via voucher equality

Published Mar 31, 2026 · Updated Mar 31, 2026

Authentication bypass in the tempo/session close handler in mppx before 0.4.11 allows remote attackers to close payment channels for free. The handleClose function accepts a signed close voucher whose cumulativeAmount equals the on-chain settled value because it tests only for a lower value. No privileges or user interaction are required, but the attacker must possess a valid channel voucher; acceptance closes or griefs that channel without committing new funds.

CVSS severity7.5
High
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Authentication bypass in the tempo/session close handler in mppx before 0.4.11 allows remote attackers to close payment channels for free. The handleClose function accepts a signed close voucher whose cumulativeAmount equals the on-chain settled value because it tests only for a lower value. No privileges or user interaction are required, but the attacker must possess a valid channel voucher; acceptance closes or griefs that channel without committing new funds.

The record

CVE
CVE-2026-34209
Published
Mar 31, 2026
Updated
Mar 31, 2026
Vendor
wevm
Product
mppx
Classifications
CWE-294
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 31, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 31, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.4.11

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

wevm · mppxversion=< 0.4.11

Published CVSS scores

7.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-294Authentication Bypass by Capture-replay

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo