Static memo configuration in mpp Tempo disables per-challenge attribution binding, enabling third-party replay
Authentication Bypass by Capture-replay in ZenHive mpp allows an unauthenticated third party to obtain paid resources by replaying a transfer settled by an unrelated payer. MPP.Methods.Tempo normally binds a settled TIP-20 TransferWithMemo to the specific challenge under verification through an attribution nonce carried in the memo. When a static "memo" is configured in method_config, check_matched_memo_binding/3 returns the match unconditionally and that binding is skipped, leaving only token, recipient, amount and the static memo value to match on. The static memo is echoed in every unauthenticated 402 response and Tempo transfers are public, so an attacker can take any matching transfer paid by a legitimate customer, request a fresh challenge for the same route, and present that transaction hash as a type="hash" credential. The hash path performs no sender or signature check tying the presenter to the wallet that broadcast the transfer. This issue affects mpp: from 0.6.1 before 0.6.4.
- Published
- Aug 19, 2026
- Updated
- Sep 10, 2026
- EPSS
- 0.6% · 47th percentile
- CWE
- CWE-294
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Report tools
Action score
32
Monitor
Low priority for now.
- CVSS
- 32 / 40 · 8.2 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.6%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · EEF
- 8.2
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| zenhive | machine payments protocol | cpe:2.3:a:zenhive:machine_payments_protocol |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- zenhive machine payments protocol0.6.1 and later · before 0.6.4
Versions reported by the vendor
Affected version ranges reported by the assigning authority (EEF). Independent of NVD's CPE analysis and usually ahead of it.
ZenHive mpp
- 0.6.1 and later · before 0.6.4affected · semver
- 542a525563c2fcedd670b593437deca81c6797a4 and later · before 2207d7f456ae14c1d3fcacc6f635bf4f8cee1a34affected · git
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Hex | mpp | from 0.6.1 · before 0.6.4 | 0.6.4 |
Same product
zenhive: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-67581On-chain transfer proof is not single-use in mpp EVM payment method, enabling cross-challenge replay34Monitor
- CVE-2026-73541Tempo fee sponsorship in mpp bounds each transaction but not aggregate exposure, allowing concurrent sponsor-wallet drain33Monitor
- CVE-2026-73829Non-atomic hash-credential dedup in mpp Tempo allows replay of a confirmed payment under a concurrent race25Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| ZenHive mpp | 0.6.4 | Vendor (CNA) |
| ZenHive mpp | 2207d7f456ae14c1d3fcacc6f635bf4f8cee1a34 | Vendor (CNA) |
| Hex:mpp | 0.6.4 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- E.FUfinder
- Jonatan Männchen / EEFanalyst
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-675810 days apartOn-chain transfer proof is not single-use in mpp EVM payment method, enabling cross-challenge replay34Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-294 · Authentication Bypass by Capture-replayCVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Session SidejackingCAPEC-102likelihood: High · High
- KerberoastingCAPEC-509High
- Remote Services with Stolen CredentialsCAPEC-555Very High
- Windows Admin Shares with Stolen CredentialsCAPEC-561
- Reusing Session IDs (aka Session Replay)CAPEC-60likelihood: High · High
- Use of Captured Hashes (Pass The Hash)CAPEC-644likelihood: Medium · High
- Use of Captured Tickets (Pass The Ticket)CAPEC-645likelihood: Low · High
- Use of Known Kerberos CredentialsCAPEC-652likelihood: Medium · High
ATT&CK techniques
- Remote ServicesT1021
- Remote Services:SMB/Windows Admin SharesT1021.002
- Email Collection:Remote Email CollectionT1114.002
- External Remote ServicesT1133
- Access Token Manipulation:Token Impersonation/TheftT1134.001
- Use Alternate Authentication Material:Pass The HashT1550.002
- Use Alternate Authentication Material:Pass The TicketT1550.003
- Use Alternate Authentication Material:Web Session CookieT1550.004
- Adversary-in-the-MiddleT1557
- Steal or Forge Kerberos TicketsT1558
- Steal or Forge Kerberos Tickets:KerberoastingT1558.003
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- cna.erlef.org/cves/CVE-2026-73136.html
- github.com/ZenHive/mpp/commit/2207d7f456ae14c1d3fcacc6f635bf4f8cee1a34
- github.com/ZenHive/mpp/security/advisories/GHSA-34g7-vx6g-82mq
- osv.dev/vulnerability/EEF-CVE-2026-73136
Vendor advisories and official records. Exploit/PoC links are deliberately left out.