GHSA-29h2-jr22-frmh: @openzeppelin/confidential contracts A Malicious ERC-7984 Token Is Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-29h2-jr22-frmh",
  "modified" : "2026-09-25T19:31:08Z",
  "published" : "2026-09-25T19:31:08Z",
  "aliases" : [ ],
  "summary" : "OpenZeppelin Confidential Contracts `VestingWalletConfidential`: a malicious ERC-7984 token is able to extract private data from the vesting wallet",
  "details" : "### Impact\n\nTwo locations consume an encrypted handle returned by an untrusted external party and use it without verifying that the party is ACL-authorized on it.\n\n#### `VestingWalletConfidential`\n\nMalicious users can call `release` with a malicious token. This token could return an alternative handle on `confidentialBalanceOf`, which represents the balance of the vesting wallet on an alternative ERC-7984 token (or any other handle that the vesting wallet has access to). The vesting wallet does not check that the token has ACL access and grants access to a new handle derived from the returned handle.\n\nEffectively, this bug allows a malicious user to gain information about any private `euint64` handle that the vesting wallet has access to via a malicious ERC-7984 token. There is no loss of funds.\n\n#### ERC7984\n\nOn a transfer with callback, `ERC7984` uses the `ebool` returned by the\nrecipient's `IERC7984Receiver.onConfidentialTransferReceived` to drive the refund\nlogic, without checking that the recipient has ACL access to it. A malicious recipient\ncan return any `ebool` the token has access to and recover its plaintext from the\nrefund result, which the token grants the caller access to. The leak is limited\nto `ebool` handles (the value is only used as an `FHE.select` condition), and\nthere is no loss of funds.\n\n### Patches\n\nBoth issues were fixed in the same patch releases: v0.5.2, v0.4.2, v0.3.2\n\n- `VestingWalletConfidential`: 93e75ceed2b9648f53f9d133f431064353456805 (#423).\n- `ERC7984` transfer callback: fe0863af2c9dce7614acce98720a913bf6a767a5 (#428), with follow-up ee47edf189ab681cebdad18bfb53dee541987be2 (#431) permitting an uninitialized returned handle.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@openzeppelin/confidential-contracts"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.3.2"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@openzeppelin/confidential-contracts"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.4.0-rc.0"
      }, {
        "fixed" : "0.4.2"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@openzeppelin/confidential-contracts"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.5.0-rc.0"
      }, {
        "fixed" : "0.5.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/OpenZeppelin/openzeppelin-confidential-contracts/security/advisories/GHSA-29h2-jr22-frmh"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/OpenZeppelin/openzeppelin-confidential-contracts/pull/423"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/OpenZeppelin/openzeppelin-confidential-contracts/pull/428"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/OpenZeppelin/openzeppelin-confidential-contracts/pull/431"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/OpenZeppelin/openzeppelin-confidential-contracts/commit/93e75ceed2b9648f53f9d133f431064353456805"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/OpenZeppelin/openzeppelin-confidential-contracts/commit/ee47edf189ab681cebdad18bfb53dee541987be2"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/OpenZeppelin/openzeppelin-confidential-contracts/commit/fe0863af2c9dce7614acce98720a913bf6a767a5"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/OpenZeppelin/openzeppelin-confidential-contracts"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/OpenZeppelin/openzeppelin-confidential-contracts/releases/tag/v0.3.2"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/OpenZeppelin/openzeppelin-confidential-contracts/releases/tag/v0.4.2"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/OpenZeppelin/openzeppelin-confidential-contracts/releases/tag/v0.5.2"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-284" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-25T19:31:08Z",
    "nvd_published_at" : null
  }
}