🛡️ CVE-2026-34209 — mppx

🟠 CVSS 8.0 — High ✅ No Known Exploit CWE-294 OSV
8.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

mppx: Tempo has a session close voucher bypass vulnerability due to settled amount equality

Impact

The tempo/session cooperative close handler validated the close voucher amount using < instead of <= against the on-chain settled amount. An attacker could submit a close voucher exactly equal to the settled amount, which would be accepted without committing any new funds, effectively closing or griefing the channel for free.

Patches

Fixed in 0.4.11.

Workarounds

There are no workarounds available for this vulnerability.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity high, availability none.

Weakness class

CVE-2026-34209 is classified as CWE-294: Authentication Bypass by Capture-replay. A captured authentication exchange can be replayed later because it is not bound to a single use.

Affected software

CVE-2026-34209 is recorded against 1 package.

  • mppx

Timeline and source

Published on 29 March 2026 and last revised on 24 July 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from OSV.

References

github.com (Web)
nvd.nist.gov (Advisory)
github.com (Web)
github.com (Package)
github.com (Web)

Details

Severity HIGH
CVSS Score 8.0
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CWE CWE-294
Public Exploit ✅ No
Source OSV
Published 2026-03-29
Updated 2026-08-12
Modified 2026-07-24

Affected Packages

Software From version Fixed in
mppx — —

Similar Threats

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