Circuit Soundness Flaw in Payy Ethereum L2 zk-Rollup
CVE-2026-48100

8.7HIGH

Key Information:

Vendor

Polybase

Status
Payy
Vendor
CVE Published:
28 September 2026

What is CVE-2026-48100?

Payy, an Ethereum L2 zk-rollup solution, has a circuit soundness failure prior to version 1.3.0. The issue arises when agg_agg forwards a compact message stream into a public array without validating the unused portion. This flaw enables a registered prover to create a valid proof that includes a burn message not derived from inner proofs, leading to unauthorized USDC transfers from the rollup contract. Although current deployments limit direct submissions of these invalid proofs to allowlisted provers, the permissioned model described in the Payy whitepaper allows a potential attacker to exploit this flaw by assuming the identity of a registered prover. This vulnerability was corrected in version 1.3.0.

Affected Version(s)

payy < 1.3.0

References

https://github.com/polybase/payy/security/advisories/GHSA...
x_refsource_CONFIRM

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.