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CVE-2023-40014

OpenZeppelin Contracts's ERC2771Context with custom forwarder may lead to zero-valued _msgSender

MEDIUM
5.3
CVSS Score
Published: August 10, 2023 at 07:52 PM UTC
Updated: June 17, 2026 at 06:15 AM UTC
2 products affected across 1 vendorOpenzeppelin ContractsOpenzeppelin Contracts Upgradable

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.7%
SSVC
No known exploit

Description

OpenZeppelin Contracts is a library for secure smart contract development. Starting in version 4.0.0 and prior to version 4.9.3, contracts using `ERC2771Context` along with a custom trusted forwarder may see `_msgSender` return `address(0)` in calls that originate from the forwarder with calldata shorter than 20 bytes. This combination of circumstances does not appear to be common, in particular it is not the case for `MinimalForwarder` from OpenZeppelin Contracts, or any deployed forwarder the team is aware of, given that the signer address is appended to all calls that originate from these forwarders. The problem has been patched in v4.9.3.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Openzeppelin Contracts· Openzeppelinnpm
95%
v < 4.9.34.0.0 ≤ v < 4.9.34.0.0
Affected range stops below 4.9.3, so it looks safe — our inference, not a vendor statement
Openzeppelin Contracts Upgradable· Openzeppelinnpm
95%
4.0.0 ≤ v < 4.9.3
Affected range stops below 4.9.3, so it looks safe — our inference, not a vendor statement

References (6)

x_refsource_MISCPatch
Source: [email protected]
https://github.com/OpenZeppelin/openzeppelin-contracts/commit/9445f96223041abf2bf08daa56f8da50b674cbcd
x_refsource_MISCPatch
Source: [email protected]
https://github.com/OpenZeppelin/openzeppelin-contracts/commit/e4435eed757d4309436b1e06608e97b6d6e2fdb5
x_refsource_MISCPatchVendor Advisory
Source: [email protected]
https://github.com/OpenZeppelin/openzeppelin-contracts/pull/4481
x_refsource_MISCPatchVendor Advisory
Source: [email protected]
https://github.com/OpenZeppelin/openzeppelin-contracts/pull/4484
x_refsource_MISCRelease Notes
Source: [email protected]
https://github.com/OpenZeppelin/openzeppelin-contracts/releases/tag/v4.9.3
x_refsource_CONFIRMVendor Advisory
Source: [email protected]
https://github.com/OpenZeppelin/openzeppelin-contracts/security/advisories/GHSA-g4vp-m682-qqmp

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-116

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