TI-2026-60087 Aliases CVE-2026-88255 GHSA-p7v4-jpp9-2m3q

mpp Tempo keys its pre-broadcast dedup reserve on the caller-supplied transaction…

LOW 29CWE-1289Published 2026-09-16 · Updated 2026-09-16

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Attack requirements: Present
Impact type: —
Confidentiality · integrity · availability: None · Low · None
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

Improper Validation of Unsafe Equivalence in Input in ZenHive mpp allows an unauthenticated remote client to pass the Tempo duplicate-submission gate twice with one signed transaction. MPP.Methods.Tempo reserves the pre-broadcast dedup slot on the caller-supplied hex in reserve_hash_atomic/2, keyed through store_key/1 on tx.raw rather than on a canonical form of the transaction. The deserializer stores the caller's hex verbatim and accepts both recovery-id encodings, so one signed transaction submitted once with v=27 and once with v=0 yields two distinct reserve keys, and both pass the reserve and reach the broadcast path. The plug-level credential replay store is deliberately carved out for tempo in lib/mpp/replay.ex, leaving this reserve as the only gate, and the post-broadcast mark writes the canonical hash key that the raw-keyed reserve never reads. What the duplicate submission yields depends on the node: a nonce-reuse rejection fails closed, while a node that answers with the canonical hash for an already-known transaction returns a second valid Payment-Receipt for a single on-chain payment. This issue affects mpp: from 0.2.0 before 0.16.2.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00524 44th percentileScored 2026-11-07

Fix Fixed mpp (ZenHive): 0.16.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
ZenHive	mpp	0.2.0 to before 0.16.2	0.16.2	Patch available	CNA

mpp VendorZenHive Affected 0.2.0 to before 0.16.2 Fixed in 0.16.2 Patch available CNA

CPE names CNA · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:ZenHive:mpp::::::::	—	—	—

cpe:2.3:a:ZenHive:mpp:*:*:*:*:*:*:*:* Versions — — ·—

Remediation

Fix · CNA mpp (ZenHive) Fixed in 0.16.2

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

Release · 2026-09-16
ZenHive mpp 0.16.2
2 records Highest priority Priority LOW 2 LOW
Other records, highest priority first
- TI-2026-60406 mpp writes Payment-Receipt and Cache-Control before the wrapped application runs, letting…Priority LOW 29
Show all 2 records →

Timeline

2026-10-02 Threatist record created from CVE-2026-88255
2026-10-03 Alias added: GHSA-p7v4-jpp9-2m3q

References

Patch 1

Fix commit e12bd4a in ZenHive/mpp

Advisory 1

GitHub Advisory

Other 3

TI-2026-42571 Unbounded max_fee_per_gas in mpp Tempo fee-payer enables single-request wallet drain CVSS 4.0HIGH 8.3
TI-2026-42570 Unbounded access list in mpp Tempo fee-payer inflates gas cost per payment CVSS 4.0HIGH 8.3
TI-2026-42392 Missing gas_limit validation in mpp Tempo fee-payer enables wallet drain CVSS 4.0HIGH 8.2
TI-2026-60473 Session voucher adding no new funds is accepted without a charge in mpp, serving paid resources for free CVSS 4.0HIGH 7.1
TI-2026-47746 On-chain transfer proof is not single-use in mpp EVM payment method, enabling cross-challenge replay CVSS 4.0HIGH 8.7
TI-2026-51635 Resource allocation without limits in ZenHive mpp CVSS 4.0HIGH 8.3

See all 12 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences