{"id":"EUVD-2026-13881","revision":null,"records":[{"revision":"e60b953536fd451a8aefaf5a743b4c23","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-33228","aliases":[],"title":"flatted: Prototype Pollution via parse()","description":"flatted is a circular JSON parser. Prior to version 3.4.2, the parse() function in flatted can use attacker-controlled string values from the parsed JSON as direct array index keys, without validating that they are numeric. Since the internal input buffer is a JavaScript Array, accessing it with the key \"__proto__\" returns Array.prototype via the inherited getter. This object is then treated as a legitimate parsed value and assigned as a property of the output object, effectively leaking a live reference to Array.prototype to the consumer. Any code that subsequently writes to that property will pollute the global prototype. This issue has been patched in version 3.4.2.","state":0,"publishedAt":"2026-03-20T23:06:48.485+00:00","modifiedAt":"2026-09-07T12:05:12.907+00:00","affected":[{"ecosystem":"Vendor product","name":"flatted","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"WebReflection\",\n                    \"product\": \"flatted\",\n                    \"versions\": [\n                        {\n                            \"version\": \"< 3.4.2\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P","score":8.9,"severity":"HIGH"}],"references":["https://github.com/WebReflection/flatted/security/advisories/GHSA-rf6f-7fwh-wjgh","https://github.com/WebReflection/flatted/commit/885ddcc33cf9657caf38c57c7be45ae1c5272802","https://github.com/WebReflection/flatted/releases/tag/v3.4.2"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-33228","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-33228","identifiers":["CVE-2026-33228"]},"retained":false,"historicalAffected":[]},{"revision":"a7fa9dd5d08b41d79a328bb90cd99e44","observedAt":"2026-11-11T08:36:00.697+00:00","statement":{"source":"euvd","id":"EUVD-2026-13881","aliases":["CVE-2026-33228","GHSA-rf6f-7fwh-wjgh"],"title":"flatted is a circular JSON parser. Prior to version 3.4.2, the parse() function in flatted can use attacker-controlled string values from the parsed JSON as direct array index keys, without validating that they are numeric. Since the intern…","description":"flatted is a circular JSON parser. Prior to version 3.4.2, the parse() function in flatted can use attacker-controlled string values from the parsed JSON as direct array index keys, without validating that they are numeric. Since the internal input buffer is a JavaScript Array, accessing it with the key \"__proto__\" returns Array.prototype via the inherited getter. This object is then treated as a legitimate parsed value and assigned as a property of the output object, effectively leaking a live reference to Array.prototype to the consumer. Any code that subsequently writes to that property will pollute the global prototype. This issue has been patched in version 3.4.2.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P","score":8.9,"severity":null}],"references":["https://github.com/WebReflection/flatted/security/advisories/GHSA-rf6f-7fwh-wjgh","https://github.com/WebReflection/flatted/commit/885ddcc33cf9657caf38c57c7be45ae1c5272802","https://github.com/WebReflection/flatted/releases/tag/v3.4.2"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-13881","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"Mar 20, 2026, 11:06:48 PM","dateUpdated":"Sep 7, 2026, 12:05:12 PM"},"relatedAdvisories":[{"id":"msrc_CVE-2026-33228","title":"flatted: Prototype Pollution via parse()","vulnerabilityIds":["CVE-2026-33228"]},{"id":"RHSA-2026:86618","title":"Red Hat Security Advisory: New container image: rhceph-9.2","vulnerabilityIds":["CVE-2023-46159","CVE-2024-47866","CVE-2024-48916","CVE-2024-55565","CVE-2025-12816","CVE-2025-15599","CVE-2025-26791","CVE-2025-30156","CVE-2025-50181","CVE-2025-50182","CVE-2025-58754","CVE-2025-59343","CVE-2025-62718","CVE-2025-66030","CVE-2025-66035","CVE-2025-66412","CVE-2025-69873","CVE-2026-0540","CVE-2026-21441","CVE-2026-22610","CVE-2026-25639","CVE-2026-26996","CVE-2026-27903","CVE-2026-27904","CVE-2026-27970","CVE-2026-32141","CVE-2026-33228","CVE-2026-33671","CVE-2026-33672","CVE-2026-33891","CVE-2026-33894","CVE-2026-33895","CVE-2026-33896","CVE-2026-39865","CVE-2026-40175","CVE-2026-40895","CVE-2026-41238","CVE-2026-41239","CVE-2026-41240","CVE-2026-41305","CVE-2026-42033","CVE-2026-42034","CVE-2026-42035","CVE-2026-42036","CVE-2026-42037","CVE-2026-42038","CVE-2026-42039","CVE-2026-42040","CVE-2026-42041","CVE-2026-42042","CVE-2026-42043","CVE-2026-42044","CVE-2026-50152","CVE-2026-58224"]},{"id":"RHSA-2026:9742","title":"Red Hat Security Advisory: Red Hat Developer Hub 1.8.6 release.","vulnerabilityIds":["CVE-2025-62718","CVE-2025-69534","CVE-2025-69873","CVE-2026-1525","CVE-2026-1526","CVE-2026-1528","CVE-2026-2229","CVE-2026-3118","CVE-2026-4800","CVE-2026-4926","CVE-2026-25679","CVE-2026-26996","CVE-2026-27601","CVE-2026-27904","CVE-2026-29063","CVE-2026-29074","CVE-2026-29186","CVE-2026-32141","CVE-2026-33036","CVE-2026-33228","CVE-2026-33891","CVE-2026-33894","CVE-2026-33895","CVE-2026-33896","CVE-2026-39983","CVE-2026-40175"]},{"id":"RHSA-2026:34342","title":"Red Hat Security Advisory: Cluster Observability Operator 1.5.0","vulnerabilityIds":["CVE-2020-7753","CVE-2021-33623","CVE-2024-4068","CVE-2024-45338","CVE-2024-52011","CVE-2025-22868","CVE-2025-22870","CVE-2025-22872","CVE-2025-47911","CVE-2025-58190","CVE-2026-1526","CVE-2026-1528","CVE-2026-2229","CVE-2026-4800","CVE-2026-4867","CVE-2026-6321","CVE-2026-6322","CVE-2026-6734","CVE-2026-9277","CVE-2026-9697","CVE-2026-12143","CVE-2026-12151","CVE-2026-25680","CVE-2026-25681","CVE-2026-29063","CVE-2026-32141","CVE-2026-33228","CVE-2026-33671","CVE-2026-33814","CVE-2026-33891","CVE-2026-33894","CVE-2026-33895","CVE-2026-33896","CVE-2026-33937","CVE-2026-33938","CVE-2026-33939","CVE-2026-33940","CVE-2026-33941","CVE-2026-39821","CVE-2026-42506","CVE-2026-48779"]},{"id":"RHSA-2026:13826","title":"Red Hat Security Advisory: Red Hat Developer Hub 1.9.4 release.","vulnerabilityIds":["CVE-2025-62718","CVE-2025-69534","CVE-2026-1525","CVE-2026-1526","CVE-2026-1528","CVE-2026-2229","CVE-2026-3118","CVE-2026-4800","CVE-2026-4926","CVE-2026-27601","CVE-2026-27904","CVE-2026-29063","CVE-2026-29074","CVE-2026-29186","CVE-2026-32141","CVE-2026-32280","CVE-2026-32282","CVE-2026-33228","CVE-2026-33891","CVE-2026-33894","CVE-2026-33895","CVE-2026-33896","CVE-2026-39983","CVE-2026-40175","CVE-2026-40895"]}],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON."},"key":"euvd:EUVD-2026-13881","identifiers":["EUVD-2026-13881","CVE-2026-33228","GHSA-rf6f-7fwh-wjgh"]},"retained":false,"historicalAffected":[]},{"revision":"d84fd50e77754ee285e207c9abfebc3c","observedAt":"2026-10-25T08:17:18.375+00:00","statement":{"source":"nvd","id":"CVE-2026-33228","aliases":[],"title":"flatted is a circular JSON parser. Prior to version 3.4.2, the parse() function in flatted can use attacker-controlled string values from the parsed JSON as direct array index keys, without validating that they are numeric. Since the intern…","description":"flatted is a circular JSON parser. Prior to version 3.4.2, the parse() function in flatted can use attacker-controlled string values from the parsed JSON as direct array index keys, without validating that they are numeric. Since the internal input buffer is a JavaScript Array, accessing it with the key \"__proto__\" returns Array.prototype via the inherited getter. This object is then treated as a legitimate parsed value and assigned as a property of the output object, effectively leaking a live reference to Array.prototype to the consumer. Any code that subsequently writes to that property will pollute the global prototype. This issue has been patched in version 3.4.2.","state":0,"publishedAt":"2026-03-20T23:16:46.51+00:00","modifiedAt":"2026-09-04T13:18:55.12+00:00","affected":[],"metrics":[{"system":"CVSS 4.0 · security-advisories@github.com · Secondary","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","score":8.9,"severity":"HIGH"},{"system":"CVSS 3.1 · nvd@nist.gov · Primary","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"},{"system":"CVSS 3.1 · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c · Secondary","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://github.com/WebReflection/flatted/commit/885ddcc33cf9657caf38c57c7be45ae1c5272802","https://github.com/WebReflection/flatted/releases/tag/v3.4.2","https://github.com/WebReflection/flatted/security/advisories/GHSA-rf6f-7fwh-wjgh","https://access.redhat.com/errata/RHSA-2026:13826","https://access.redhat.com/errata/RHSA-2026:34342","https://access.redhat.com/errata/RHSA-2026:9742","https://access.redhat.com/security/cve/CVE-2026-33228","https://bugzilla.redhat.com/show_bug.cgi?id=2449872","https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33228.json"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-33228","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Modified","weaknesses":["CWE-1321","CWE-915"],"productCriteria":["cpe:2.3:a:webreflection:flatted:*:*:*:*:*:node.js:*:*"],"sourceDates":{"published":"2026-03-20T23:16:46.510","lastModified":"2026-09-04T13:18:55.120"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-33228","identifiers":["CVE-2026-33228"]},"retained":false,"historicalAffected":[]},{"revision":"1e6f0180abec4b76a3cdbd2430254898","observedAt":"2026-10-24T13:17:17.793+00:00","statement":{"source":"osv","id":"GHSA-rf6f-7fwh-wjgh","aliases":["CVE-2026-33228"],"title":"Prototype Pollution via parse() in NodeJS flatted","description":"---\n  **Summary**\n\n  The parse() function in flatted can use attacker-controlled string values from the parsed JSON as direct array index\n  keys, without validating that they are numeric. Since the internal input buffer is a JavaScript Array, accessing it\n  with the key \"\\_\\_proto\\_\\_\" returns Array.prototype via the inherited getter. This object is then treated as a legitimate\n   parsed value and assigned as a property of the output object, effectively leaking a live reference to Array.prototype\n   to the consumer. Any code that subsequently writes to that property will pollute the global prototype.\n\n  ---\n  **Root Cause**\n\n  File: esm/index.js:29 (identical in cjs/index.js)\n```\n  const resolver = (input, lazy, parsed, $) => output => {\n    for (let ke = keys(output), {length} = ke, y = 0; y < length; y++) {\n      const k = ke[y];\n      const value = output[k];    \n      if (value instanceof Primitive) {\n        const tmp = input[value];      // Bug is here\n```\n\nNo validation that value is a safe numeric index input is built as a plain Array. JavaScript's property lookup on arrays traverses the prototype chain for non-numeric  keys. The key \"\\_\\_proto\\_\\_\" resolves to Array.prototype, which:\n\n  - has type \"object\" → passes the typeof tmp === object guard at line 30\n  - is not in the parsed Set yet → passes the !parsed.has(tmp) guard.\n  - The reference to Array.prototype is then enqueued in lazy and later unconditionally assigned to the output object.\n  ---\n  **Replication Steps**\n```\n  const Flatted = require('flatted'); \n  const parsed = Flatted.parse('[{\"x\":\"__proto__\"}]');\n  parsed.x.polluted = 'pwned';\n  console.log([].polluted);  // Returns true\n``` \n ---\n  **Impact**\n An attacker can supply a crafted flatted string to parse() that causes the returned object to hold a live reference to Array.prototype, enabling any downstream code that writes to that property to pollute the global prototype chain, potentially causing denial of service or code execution.\n\n  **Recommended solution**\n Validate that the index string represents an integer within the bounds of input before accessing it:\n\n  // Before (vulnerable)\n  const tmp = input[value];\n\n  // After (safe)\n  const idx = +value;  // coerce boxed String → number\n  const tmp = (Number.isInteger(idx) && idx >= 0 && idx < input.length)\n    ? input[idx]\n    : undefined;","state":0,"publishedAt":"2026-03-19T17:43:54+00:00","modifiedAt":"2026-10-05T16:00:04.586756+00:00","affected":[{"ecosystem":"npm","name":"flatted","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"3.4.2"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V4","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"HIGH"}],"references":["https://github.com/WebReflection/flatted/security/advisories/GHSA-rf6f-7fwh-wjgh","https://nvd.nist.gov/vuln/detail/CVE-2026-33228","https://github.com/WebReflection/flatted/commit/885ddcc33cf9657caf38c57c7be45ae1c5272802","https://access.redhat.com/errata/RHSA-2026:13826","https://access.redhat.com/errata/RHSA-2026:34342","https://access.redhat.com/errata/RHSA-2026:9742","https://access.redhat.com/security/cve/CVE-2026-33228","https://bugzilla.redhat.com/show_bug.cgi?id=2449872","https://github.com/WebReflection/flatted","https://github.com/WebReflection/flatted/releases/tag/v3.4.2"],"sourceUrl":"https://github.com/advisories/GHSA-rf6f-7fwh-wjgh","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-rf6f-7fwh-wjgh","identifiers":["GHSA-rf6f-7fwh-wjgh","CVE-2026-33228"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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Not a global EPSS backfill.","generation":"2026-11-11T17:59:29.7133238+00:00","complete":true,"records":1097,"lastAttemptAt":"2026-11-11T17:59:29.7133238+00:00","lastSuccessAt":"2026-11-11T17:59:29.8793973+00:00","error":null,"lastVerifiedAt":"2026-11-11T17:59:29.8793975+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"nvd","scope":"Rolling NVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global NVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-9169816ed33d4259981dbb50309d6730","complete":false,"records":13753,"lastAttemptAt":"2026-11-11T18:01:00.7925805+00:00","lastSuccessAt":"2026-11-11T16:59:52.052+00:00","error":"100 identifier lookups failed; latest failures include request timeout. 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