What is CVE-2023-49798?

OpenZeppelin Contracts is a library for smart contract development. A merge issue when porting the 5.0.1 patch to the 4.9 branch caused a line duplication. In the version of `Multicall.sol` released in `@openzeppelin/contracts@4.9.4` and `@openzeppelin/contracts-upgradeable@4.9.4`, all subcalls are executed twice. Concretely, this exposes a user to unintentionally duplicate operations like asset transfers. The duplicated delegatecall was removed in version 4.9.5. The 4.9.4 version is marked as deprecated. Users are advised to upgrade. There are no known workarounds for this issue.

How severe is CVE-2023-49798?

CVE-2023-49798 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2023-49798 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-49798?

CVE-2023-49798 primarily affects Openzeppelin Contracts. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-49798?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2023-49798 published?

CVE-2023-49798 was published on 2023-12-09 and last updated on 2026-06-17.

CVE-2023-49798

CVE-2023-49798 is a medium-severity vulnerability in Openzeppelin Contracts with a CVSS 3.x base score of 5.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-670.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-670
Affected product: Openzeppelin Contracts
Published: 2023-12-09
Last modified: 2026-06-17

Description

OpenZeppelin Contracts is a library for smart contract development. A merge issue when porting the 5.0.1 patch to the 4.9 branch caused a line duplication. In the version of `Multicall.sol` released in `@openzeppelin/[email protected]` and `@openzeppelin/[email protected]`, all subcalls are executed twice. Concretely, this exposes a user to unintentionally duplicate operations like asset transfers. The duplicated delegatecall was removed in version 4.9.5. The 4.9.4 version is marked as deprecated. Users are advised to upgrade. There are no known workarounds for this issue.

Frequently asked questions

What is CVE-2023-49798?: OpenZeppelin Contracts is a library for smart contract development. A merge issue when porting the 5.0.1 patch to the 4.9 branch caused a line duplication. In the version of `Multicall.sol` released in `@openzeppelin/[email protected]` and `@openzeppelin/[email protected]`, all subcalls are executed twice. Concretely, this exposes a user to unintentionally duplicate operations like asset transfers. The duplicated delegatecall was removed in version 4.9.5. The 4.9.4 version is marked as deprecated. Users are advised to upgrade. There are no known workarounds for this issue.
How severe is CVE-2023-49798?: CVE-2023-49798 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2023-49798 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-49798?: CVE-2023-49798 primarily affects Openzeppelin Contracts. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-49798?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2023-49798 published?: CVE-2023-49798 was published on 2023-12-09 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:openzeppelin:contracts:4.9.4:*:*:*:*:node.js:*:*
cpe:2.3:a:openzeppelin:contracts_upgradeable:4.9.4:*:*:*:*:node.js:*:*

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