CVE-2026-88255

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Source
https://cve.org/CVERecord?id=CVE-2026-88255
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-88255.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-88255
Aliases
Published
2026-09-16T08:24:40Z
Modified
2026-09-18T03:48:32Z
Severity
  • 6.3 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N CVSS Calculator
Summary
mpp Tempo keys its pre-broadcast dedup reserve on the caller-supplied transaction encoding, so a re-encoded signed transaction reserves a second slot
Details

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.

Database specific 
{
    "cna_assigner":  "EEF",
    "cwe_ids":  [
        "CWE-1289"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/88xxx/CVE-2026-88255.json",
    "unresolved_ranges":  [
        {
            "extracted_events":  [
                {
                    "introduced":  "f8904666061fbab695874856d8fcd02c471dfe1b"
                },
                {
                    "fixed":  "e12bd4a1cea2e97c2a01fc059c48e5594a7b4a43"
                }
            ],
            "source":  "AFFECTED_FIELD"
        }
    ]
}
References

Affected packages

Git / github.com/zenhive/mpp

Affected ranges

Type
GIT
Repo
https://github.com/zenhive/mpp
Events
Introduced
7ca7538f05959a98e0e5e63e4bd949b4f362cf8d
Fixed
3b7e43abf60fa30c40985e4043965ec67791b4dc
Fixed
e12bd4a1cea2e97c2a01fc059c48e5594a7b4a43
Fixed
f8904666061fbab695874856d8fcd02c471dfe1b
Database specific
Show details 
{
    "extracted_events":  [
        {
            "introduced":  "0.2.0"
        },
        {
            "fixed":  "0.16.2"
        }
    ],
    "source":  [
        "DESCRIPTION",
        "REFERENCES"
    ]
}

Affected versions

v0.*
v0.10.0
v0.11.0
v0.12.0
v0.13.0
v0.14.0
v0.15.0
v0.16.0
v0.16.1
v0.2.0
v0.3.0
v0.4.0
v0.5.1
v0.6.0
v0.6.1
v0.6.3
v0.6.4
v0.7.0
v0.8.0
v0.9.0

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-88255.json"