parse-nested-form-data has Prototype Pollution via `__proto__` in FormData field names

Summary parseFormData walks bracket and dot-notation FormData field names into nested objects without filtering reserved property keys. A single FormData field whose name begins with proto, or contains .proto. mid-path, causes the parser to traverse onto Object.prototype and assign properties...

CVE-2026-35209 defu: Prototype pollution via `__proto__` key in defaults argument

defu is software that allows uers to assign default properties recursively. Prior to version 6.1.5, applications that pass unsanitized user input e.g. parsed JSON request bodies, database records, or config files from untrusted sources as the first argument to defu are vulnerable to prototype...

CVE-2026-35209

CVE-2026-35209 affects defu, a recursive defaults merger. Before v6.1.5, the vulnerable code path uses Object.assign({}, defaults) in _defu, which can trigger the proto setter and pollute the Object prototype, allowing attacker-controlled values to appear in the final result. The vulnerability ar...

GHSA-W48F-FWG7-WW6P @stablelib/cbor: Prototype poisoning via `__proto__` map keys in CBOR decoding

Summary @stablelib/cbor decodes CBOR maps into ordinary JavaScript objects and assigns attacker-controlled keys directly onto those objects. A CBOR map key named proto therefore changes the prototype of the decoded object instead of becoming an ordinary data property. Details The decoder builds m...

CVE-2026-33228

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 th...

CVE-2026-33228

Flatted (JSON circular parser) is affected. Prior to 3.4.2, its parse() could treat attacker-controlled string values as direct array index keys, and using the key proto on the internal Array could expose Array.prototype to the output, enabling prototype pollution. The issue has been patched in v...

GHSA-RF6F-7FWH-WJGH Prototype Pollution via parse() in NodeJS flatted

--- Summary 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...

qs before 6.10.3, as used in Express before 4.17.3 and other products, allows attackers to cause a Node process hang for an Express application because an __ proto__ key can be used. In many typical Express use cases, an unauthenticated remote attacker can place the attack payload in the query string of the URL that is used to visit the application, such as a[__proto__]=b&a[__proto__]&a[length]=100000000. The fix was backported to qs 6.9.7, 6.8.3, 6.7.3, 6.6.1, 6.5.3, 6.4.1, 6.3.3, and 6.2.4 (and therefore Express 4.17.3, which has "deps: [email protected]" in its release description, is not vulnerable).

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