CVE-2025-46834

Alchemy's Modular Account can use executeUserOp to bypass allowlist prevalidation hook

Published May 15, 2025 CVSS 4.0 · 6.6 Medium EPSS < 1% KEV · Not listed

Description

Alchemy's Modular Account is a smart contract account that is compatible with ERC-4337 and ERC-6900. In versions on the 2.x branch prior to commit 5e6f540d249afcaeaf76ab95517d0359fde883b0, owners of Modular Accounts can grant session keys (scoped external keys) to external parties and would use the allowlist module to restrict which external contracts can be accessed by the session key. There is a bug in the allowlist module in that we don't check for the `executeUserOp` -> `execute` or `executeBatch` path, effectively allowing any session key to bypass any access control restrictions set on the session key. Session keys are able to access ERC20 and ERC721 token contracts amongst others, transferring all tokens from the account out andonfigure the permissions on external modules on session keys. They would be able to remove all restrictions set on themselves this way, or rotate the keys of other keys with higher privileges into keys that they control. Commit 5e6f540d249afcaeaf76ab95517d0359fde883b0 fixes this issue.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

alchemyplatform

modular-account

affected

Version	Status	Constraints
`= 2.0.0`	affected	—

No data.

No data available yet.

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

Source	ID	Title
EUVD	EUVD-2025-28073	Alchemy's Modular Account is a smart contract account that is compatible with ERC-4337 and ERC-6900. In versions on the 2.x branch prior to commit 5e6f540d249afcaeaf76ab95517d0359fde883b0, owners of Modular Accounts can grant session keys (scoped external keys) to external parties and would use the allowlist module to restrict which external contracts can be accessed by the session key. There is a bug in the allowlist module in that we don't check for the `executeUserOp` -> `execute` or `executeBatch` path, effectively allowing any session key to bypass any access control restrictions set on the session key. Session keys are able to access ERC20 and ERC721 token contracts amongst others, transferring all tokens from the account out andonfigure the permissions on external modules on session keys. They would be able to remove all restrictions set on themselves this way, or rotate the keys of other keys with higher privileges into keys that they control. Commit 5e6f540d249afcaeaf76ab95517d0359fde883b0 fixes this issue.

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.400% probability within 30 days)

Exploitation none

Automatable yes

Technical Impact partial

References

Link	Providers
https://github.com/alchemyplatform/modular-account/commit/5e6f540d249afcaeaf76ab95517d0359fde883b0
https://github.com/alchemyplatform/modular-account/security/advisories/GHSA-jhp7-7cq9-m4pv

History

May 19, 2025 7:15 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

May 15, 2025 7:45 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		Alchemy's Modular Account is a smart contract account that is compatible with ERC-4337 and ERC-6900. In versions on the 2.x branch prior to commit 5e6f540d249afcaeaf76ab95517d0359fde883b0, owners of Modular Accounts can grant session keys (scoped external keys) to external parties and would use the allowlist module to restrict which external contracts can be accessed by the session key. There is a bug in the allowlist module in that we don't check for the `executeUserOp` -> `execute` or `executeBatch` path, effectively allowing any session key to bypass any access control restrictions set on the session key. Session keys are able to access ERC20 and ERC721 token contracts amongst others, transferring all tokens from the account out andonfigure the permissions on external modules on session keys. They would be able to remove all restrictions set on themselves this way, or rotate the keys of other keys with higher privileges into keys that they control. Commit 5e6f540d249afcaeaf76ab95517d0359fde883b0 fixes this issue.
Title		Alchemy's Modular Account can use executeUserOp to bypass allowlist prevalidation hook
Weaknesses		CWE-863
References		https://github.com/alchemyplatform/modular-account/commit/5e6f540d249afcaeaf76ab95517d0359fde883b0 https://github.com/alchemyplatform/modular-account/security/advisories/GHSA-jhp7-7cq9-m4pv
Metrics		cvssV4_0 `{'score': 6.6, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U'}`