# CVE-2026-73136: ZenHive mpp authentication bypass in capture-replay

Source: https://junglewise.ai/threats/cve-2026-73136-zenhive-mpp-authentication-bypass-in-capture-replay  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-19. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-73136 · Severity: high · CVSS 7.5 · Published 2026-08-19

ZenHive mpp is a cryptocurrency payment processor that validates transfers to unlock access to paid resources. An attacker can bypass authentication by replaying a legitimate transfer made by another customer, allowing unauthorized access to paid services without making a payment. The vulnerability stems from insufficient validation of transaction ownership when static memo values are configured, enabling attackers to reuse transaction hashes across different requests.

Technologies: [ZenHive Machine Payments Protocol](https://junglewise.ai/threats/technologies/machine-payments-protocol), [ZenHive Mpp](https://junglewise.ai/threats/technologies/mpp). Vendors: [ZenHive](https://junglewise.ai/threats/vendors/zenhive).

## Quick answers

**Is CVE-2026-73136 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-73136 being exploited in the wild.

**How severe is CVE-2026-73136?** High severity, with a CVSS score of 7.5, published 19 August 2026.

**Which products and versions are affected?** ZenHive Mpp 0.6.1 to 0.6.3.

**Is there a fix for CVE-2026-73136?** A patch was published on 2026: Fixed in version 0.6.4 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-73136 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-73136?** Check whether you run ZenHive Machine Payments Protocol or ZenHive Mpp at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is an authentication bypass in MPP.Methods.Tempo's transaction verification logic. When a static "memo" value is configured in method_config, the check_matched_memo_binding/3 function unconditionally returns a match and skips nonce-based transaction binding, relying only on token, recipient, amount, and static memo values. Since static memos are echoed in unauthenticated 402 responses and Tempo transfers are publicly visible on-chain, an attacker can capture any legitimate transfer matching these criteria, request a fresh challenge for the same route, and present the captured transaction hash as a type="hash" credential. The hash path performs no sender or signature verification, allowing an unauthenticated user to claim ownership of any observed transfer. This is fixed in version 0.6.4 and later.

## Affected products

- ZenHive mpp 0.6.1 to 0.6.3

## Timeline

- 2026-08-19: disclosed
- 2026: patched: Fixed in version 0.6.4

## References

- [https://repo.hex.pm/](https://repo.hex.pm/)
- [https://github.com/](https://github.com/)

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