{"id":"CVE-2025-66559","url":"https://www.cyber-defence.io/tools/cve/CVE-2025-66559","generatedAt":"2026-10-28T04:35:42.338Z","title":"Result: the last verified batch could end up pointing at a transition index from the next batch (often zeroed), corrupting the verified chain pointer.","description":"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.","published":"2025-12-04T23:15:47.000Z","lastModified":"2026-10-18T15:10:00.000Z","status":"Deferred","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"4.0","score":8,"severity":"HIGH","vector":"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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-129"],"affected":[],"epss":{"score":0.00312,"percentile":0.23942,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.31%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/taikoxyz/taiko-mono/commit/379f5cb4ffe9e1945563ab2c7740bc9f4ea004d8","source":"security-advisories@github.com"},{"url":"https://github.com/taikoxyz/taiko-mono/security/advisories/GHSA-5mxh-r33p-6h5x","source":"security-advisories@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2025-66559","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}