CVE-2026-73829

Sažetak

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.

Reference

CVSS

Base:	3.7
Impact:	1.4
Exploitability:	2.2

Pristup

Vektor	Složenost	Autentikacija
NETWORK	HIGH	NONE

Impact

Povjerljivost	Cjelovitost	Dostupnost
NONE	LOW	NONE

CVSS vektor

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Zadnje važnije ažuriranje

10-09-2026 - 18:30

Objavljeno

19-08-2026 - 18:17