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Fencer Intel
medium 6.6

CVE-2025-46834 json

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

published last yr. modified 4mo ago also EUVD-2025-28073

cvss
6.6
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 34%
public exploits
0
none known

Summary

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.

Patch / fix

Is CVE-2025-46834 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
last yr.

Exploit prediction

0.40% chance of exploitation in the next 30 days, higher than 34% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 6.6 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
CNA 4.0 6.6 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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • alchemyplatform modular-account

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.