CVE-2026-73829

See a problem?
Please try reporting it to the source first.
Source
https://cve.org/CVERecord?id=CVE-2026-73829
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-73829.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-73829
Aliases
Published
2026-08-19T17:19:43Z
Modified
2026-10-28T02:30:54Z
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
Non-atomic hash-credential dedup in mpp Tempo allows replay of a confirmed payment under a concurrent race
Details

Time-of-check Time-of-use (TOCTOU) Race Condition in ZenHive mpp allows an unauthenticated remote client to redeem one confirmed on-chain payment for multiple paid-resource accesses.

The type="hash" credential path in MPP.Methods.Tempo.verify/2 guards against replay with a non-atomic check-then-mark sequence: check_hash_unused/2 reads the dedup store, an eth_getTransactionReceipt round trip verifies the payment on chain, and only then does mark_hash_used/2 write the mark. Concurrent requests carrying the same settled payment hash all pass the read before any of them writes, so each is issued a receipt. The store's atomic check_and_mark/2 primitive is available and used by the type="transaction" path, but the hash path calls plain get and put even when the configured store implements it. Exploitation requires a dedup store to be configured; the default nil store is stateless and documented as offering no replay protection at all.

This issue affects mpp: from 0.2.0 before 0.6.1.

Database specific 
{
    "cna_assigner":  "EEF",
    "cwe_ids":  [
        "CWE-367"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73829.json"
}
References

Affected packages

Git / github.com/zenhive/mpp

Affected ranges

Type
GIT
Repo
https://github.com/zenhive/mpp
Events
Introduced
7ca7538f05959a98e0e5e63e4bd949b4f362cf8d
Fixed
542a525563c2fcedd670b593437deca81c6797a4
Fixed
46c5b0e1311da7d92190dc7d9ea89027a1d365e9
Database specific
Show details 
{
    "extracted_events":  [
        {
            "cpe":  "cpe:2.3:a:zenhive:machine_payments_protocol:*:*:*:*:*:elixir:*:*",
            "range":  [
                {
                    "introduced":  "0.2.0"
                },
                {
                    "fixed":  "0.6.1"
                }
            ],
            "source":  "CPE_RANGE"
        },
        {
            "range":  [
                {
                    "fixed":  "46c5b0e1311da7d92190dc7d9ea89027a1d365e9"
                }
            ],
            "source":  "REFERENCES_COMMIT"
        }
    ]
}

Affected versions

v0.*
v0.2.0
v0.3.0
v0.4.0
v0.5.1
v0.6.0

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-73829.json"