CVE-2026-73645

OpenZeppelin Confidential Contracts is an experimental library for developing applications on the Zama fhEVM. Prior to 0.3.1, the ERC7984 contract tracked confidential total supply with an euint64 value, and an overflowing internal _mint operation could fail silently. The wrap and onTransferReceived functions in contracts/token/ERC7984/extensions/ERC7984ERC20Wrapper.sol did not handle that failure, so a user could transfer the underlying token without receiving the corresponding confidential wrapped token. With the default rate(), the wrapper fills after approximately 18.4 trillion tokens, and subsequent wrapping requests can cause loss of funds. This issue is fixed in version 0.3.1.

OpenZeppelin Confidential Contracts is an experimental library for developing applications on the Zama fhEVM. Prior to 0.3.1, the ERC7984 contract tracked confidential total supply with an euint64 value, and an overflowing internal _mint operation could fail silently. The wrap and onTransferReceived functions in contracts/token/ERC7984/extensions/ERC7984ERC20Wrapper.sol did not handle that failure, so a user could transfer the underlying token without receiving the corresponding confidential wrapped token. With the default rate(), the wrapper fills after approximately 18.4 trillion tokens, and subsequent wrapping requests can cause loss of funds. This issue is fixed in version 0.3.1.

Impact

The ERC7984 contract tracks total supply using a confidential euint64 value. If a call to the internal _mint function would result in the total supply overflowing, the call fails silently. The wrap and onTransferReceived functions in ERC7984ERC20Wrapper assume that _mint won't fail silently and do not check the return value. If the mint function fails silently, users do not receive the confidential wrapped token but still send the underlying token, resulting in a loss of funds.

By default (without overriding rate(), the wrapper fills up after wrapping ~18.4 trillion tokens. There are very few tokens of value with sufficient total supply to result in the filling of the wrapper. That said, we recommend upgrading to 0.3.1 to remove this issue.

Patches

This issue has been patched in the 0.3.1 release.

OpenZeppelin Confidential Contracts is an experimental library for developing applications on the Zama fhEVM. Prior to 0.3.1, the ERC7984 contract tracked confidential total supply with an euint64 value, and an overflowing internal _mint operation could fail silently. The wrap and onTransferReceived functions in contracts/token/ERC7984/extensions/ERC7984ERC20Wrapper.sol did not handle that failure, so a user could transfer the underlying token without receiving the corresponding confidential wrapped token. With the default rate(), the wrapper fills after approximately 18.4 trillion tokens, and subsequent wrapping requests can cause loss of funds. This issue is fixed in version 0.3.1.

OpenZeppelin Confidential Contracts is an experimental library for developing applications on the Zama fhEVM. Prior to 0.3.1, the ERC7984 contract tracked confidential total supply with an euint64 value, and an overflowing internal _mint operation could fail silently. The wrap and onTransferReceived functions in contracts/token/ERC7984/extensions/ERC7984ERC20Wrapper.sol did not handle that failure, so a user could transfer the underlying token without receiving the corresponding confidential wrapped token. With the default rate(), the wrapper fills after approximately 18.4 trillion tokens, and subsequent wrapping requests can cause loss of funds. This issue is fixed in version 0.3.1.

Impact

The ERC7984 contract tracks total supply using a confidential euint64 value. If a call to the internal _mint function would result in the total supply overflowing, the call fails silently. The wrap and onTransferReceived functions in ERC7984ERC20Wrapper assume that _mint won't fail silently and do not check the return value. If the mint function fails silently, users do not receive the confidential wrapped token but still send the underlying token, resulting in a loss of funds.

By default (without overriding rate(), the wrapper fills up after wrapping ~18.4 trillion tokens. There are very few tokens of value with sufficient total supply to result in the filling of the wrapper. That said, we recommend upgrading to 0.3.1 to remove this issue.

Patches

This issue has been patched in the 0.3.1 release.