AIKIDO-2026-10219
x402 is vulnerable to Replay Attacks
47
Medium Risk
This Affects:
x402TL;DR
Affected versions of this package are vulnerable to duplicate transaction attacks in Solana payment flows because identical transaction payloads can be generated under concurrent conditions. Since Solana rejects byte-identical transactions within the same blockhash window, attackers or high-throughput scenarios could trigger transaction collisions, leading to dropped or delayed payments. The issue is fixed by adding a unique memo with a random nonce to each transaction, ensuring every payment is distinct and preventing duplicate transaction conflicts.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range.
Background info
x402 is vulnerable to Replay Attacks in versions 0.1.0 - 2.0.0.
How to fix this
Upgrade the x402 library to the patch version.
Are You Affected?
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SOC 2Compliant
ISO 27001Compliant