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Taiko Alethia Pacaya inbox verification pointer corruption

Type: advisorySources: OSV

Taiko Alethia is an Ethereum-equivalent, permissionless, based rollup designed to scale Ethereum without compromising its fundamental properties. In 2.3.1 and earlier, TaikoInbox._verifyBatches (packages/protocol/contracts/layer1/based/TaikoInbox.sol:627-678) advanced the local tid to whatever transition matched the current blockHash before knowing whether that batch would actually be verified. When the loop later broke (e.g., cooldown window not yet passed or transition invalidated), the function still wrote that newer tid into batches[lastVerifiedBatchId].verifiedTransitionId after decrementing batchId. Result: the last verified batch could end up pointing at a transition index from the next batch (often zeroed), corrupting the verified chain pointer.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2025-66559
Confirmed fixed CVEs
Not specified
Updated in this feed
3 Nov 2026, 03:12 UTC · Revision 1

Source evidence

Taiko Alethia Pacaya inbox verification pointer corruption

core-osv · Original source

Published 4 Dec 2025, 22:23 UTC

Taiko Alethia is an Ethereum-equivalent, permissionless, based rollup designed to scale Ethereum without compromising its fundamental properties. In 2.3.1 and earlier, TaikoInbox._verifyBatches (packages/protocol/contracts/layer1/based/TaikoInbox.sol:627-678) advanced the local tid to whatever transition matched the current blockHash before knowing whether that batch would actually be verified. When the loop later broke (e.g., cooldown window not yet passed or transition invalidated), the function still wrote that newer tid into batches[lastVerifiedBatchId].verifiedTransitionId after decrementing batchId. Result: the last verified batch could end up pointing at a transition index from the next batch (often zeroed), corrupting the verified chain pointer.

osv:CVE-2025-66559
Complete source record
{
  "id": "3c4bd9762b4a31b3ab91141bb1bb7372be96a4ca935e845ef2c29c30c5440fb1",
  "url": "https://osv.dev/vulnerability/CVE-2025-66559",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Taiko Alethia Pacaya inbox verification pointer corruption",
    "summary": "Taiko Alethia is an Ethereum-equivalent, permissionless, based rollup designed to scale Ethereum without compromising its fundamental properties. In 2.3.1 and earlier, TaikoInbox._verifyBatches (packages/protocol/contracts/layer1/based/TaikoInbox.sol:627-678) advanced the local tid to whatever transition matched the current blockHash before knowing whether that batch would actually be verified. When the loop later broke (e.g., cooldown window not yet passed or transition invalidated), the function still wrote that newer tid into batches[lastVerifiedBatchId].verifiedTransitionId after decrementing batchId. Result: the last verified batch could end up pointing at a transition index from the next batch (often zeroed), corrupting the verified chain pointer.",
    "evidence": "osv:CVE-2025-66559",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2025-66559",
      "aliases": [
        "CVE-2025-66559",
        "GHSA-5mxh-r33p-6h5x"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/taikoxyz/taiko-mono",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "379f5cb4ffe9e1945563ab2c7740bc9f4ea004d8"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "2.3.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "379f5cb4ffe9e1945563ab2c7740bc9f4ea004d8"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "taiko-alethia-protocol-v2.3.0",
            "bridge-ui-v2.14.0",
            "taiko-alethia-protocol-v2.2.0",
            "fork-diff-v0.6.3",
            "fork-diff-v0.6.2",
            "taiko-alethia-protocol-v1.12.0",
            "taiko-alethia-protocol-v2.1.0",
            "protocol-v1.11.0",
            "taiko-alethia-protocol-v1.11.0",
            "taiko-client-v0.40.0",
            "bridge-ui-v2.13.0",
            "protocol-v1.10.0",
            "taiko-client-v0.39.2",
            "taiko-client-v0.39.1",
            "taiko-client-v0.39.0",
            "taiko-client-v0.38.0",
            "fork-diff-v0.6.1",
            "taiko-client-v0.37.0",
            "protocol-v1.8.0",
            "taiko-client-v0.36.0",
            "protocol-v1.9.0",
            "taiko-client-v0.34.1",
            "guardian-prover-health-check-ui-v0.2.0",
            "bridge-ui-v2.12.0",
            "snaefell-ui-v1.1.0",
            "snaefell-ui-v1.0.0",
            "bridge-ui-v2.11.0",
            "supplementary-contracts-v1.0.0",
            "blobstorage-v0.2.0",
            "branding-v0.4.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-66559.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:25.451766299Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/66xxx/CVE-2025-66559.json",
        "https://github.com/taikoxyz/taiko-mono/security/advisories/GHSA-5mxh-r33p-6h5x",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-66559",
        "https://github.com/taikoxyz/taiko-mono/commit/379f5cb4ffe9e1945563ab2c7740bc9f4ea004d8"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-129"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/66xxx/CVE-2025-66559.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-66559",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 492130,
  "published_at": "2025-12-04T22:23:55.608+00:00"
}