{"metadata": {"vulnerability": "CVE-2026-110816", "count": 10, "kinds": {"milestone": 3, "sighting": 1, "kev": 0, "other": 6}}, "data": [{"timestamp": "2026-10-14T21:40:55.805Z", "date_only": false, "value": "2026-10-14T21:40:55.805Z", "kind": "milestone", "label": "Reserved", "source": "cvelistv5", "record": "CVE-2026-110816", "field": "cveMetadata.dateReserved"}, {"timestamp": "2026-10-14T22:05:24.015Z", "date_only": false, "value": "2026-10-14T22:05:24.015Z", "kind": "milestone", "label": "Published", "source": "cvelistv5", "record": "CVE-2026-110816", "field": "cveMetadata.datePublished"}, {"timestamp": "2026-10-14T22:05:24.015Z", "date_only": false, "value": "2026-10-14T22:05:24.015Z", "kind": "other", "label": "Updated", "source": "cvelistv5 / harborist", "record": "CVE-2026-110816", "field": "containers.cna.providerMetadata.dateUpdated"}, {"timestamp": "2026-10-14T22:17:23.230Z", "date_only": false, "value": "2026-10-14T22:17:23.230", "kind": "milestone", "label": "Published", "source": "fkie_nvd \u00b7 FKIE_CVE-2026-110816", "record": "FKIE_CVE-2026-110816", "field": "published"}, {"timestamp": "2026-10-15T00:55:35.779Z", "date_only": false, "value": "2026-10-15T00:55:35.779586Z", "kind": "sighting", "label": "Seen", "source": "https://infosec.exchange/users/cve/statuses/117442194595536272", "record": "CVE-2026-110816", "field": "creation_timestamp", "uuid": "0ab2f97a-46a0-4324-b4c7-684b609f370e", "content": "CVE-2026-110816 qs.stringify with arrayFormat comma throws TypeError on array elements that cannot be coerced to a string ### Summary\n`qs.stringify` with `arrayFormat: 'comma'` throws `TypeError: Cannot convert object to primitive value` when an array element cannot be coerced to a string, such as an object with an own non-callable `toString` (`{ \"toString\": \"x\" }`) or a null-prototype object. The comma format joins array elements with `Array.prototype.join` and, under `encodeValuesOnly`, first passes each element through `String()` in `utils.encode`; neither guards against an element whose string coercion fails.\n### Details\nIn `lib/stringify.js`, the comma branch collapses the array with `obj.join(',')`. For an element whose own `toString` is not callable, `ToPrimitive` skips it, falls through to `Object.prototype.valueOf` (which returns the object itself), and throws. Under `encodeValuesOnly: true`, the same element first reaches `String(str)` in `utils.encode` (`lib/utils.js`) and throws there. Nested arrays (`{ \"a\": [[{ \"toString\": \"x\" }]] }`) throw the same way, through `Array.prototype.toString`. The `indices`, `brackets`, and `repeat` formats walk into object elements instead of coercing them, and are not affected.\nSuch elements can come from untrusted input. `JSON.parse` produces `{ \"a\": [{ \"toString\": \"x\" }] }` with no qs option involved. `qs.parse(\"a[0][toString]=x\", { allowPrototypes: true })` keeps the `toString` key, and `qs.parse(\"a[][b]=c\", { plainObjects: true })` produces a null-prototype element; the default parse options drop `toString` and produce ordinary objects, which do not throw. Express 4's default `query parser`, Express 5's `extended` query parser, and body-parser's `urlencoded({ extended: true })` all call `qs.parse` with `allowPrototypes: true`.\n#### PoC\n```js\nvar qs = require(\"qs\");\nqs.stringify(JSON.parse(\"{\\\"a\\\":[{\\\"toString\\\":\\\"x\\\"}]}\"), { arrayFormat: \"comma\" });\nqs.stringify(qs.parse(\"a[0][toString]=x\", { allowPrototypes: true }), { arrayFormat: \"comma\" });\nqs.stringify(qs.parse(\"a[][b]=c\", { plainObjects: true }), { arrayFormat: \"comma\", encodeValuesOnly: true });\n// TypeError: Cannot convert object to primitive value\n```\n#### Fix\nApplied in a952e75 on `main` and released as v6.16.1: an element whose string coercion would fail is coerced to its primitive `valueOf`, if any, or else to `Object.prototype.toString`, so it renders as `[object Object]`, the same as any other object element already does under the comma format. Nested arrays are walked the way `join` walks them. Every input that did not previously throw serializes exactly as before, and a `toString` or `valueOf` that itself throws still propagates.\n### Affected versions\n`>=6.7.0 <6.16.1`, fixed in v6.16.1.\nThe `join` path was introduced with the comma format in b84acba and first shipped in v6.7.0; v6.6.x and earlier ignore `arrayFormat: 'comma'` and are not affected. The `encodeValuesOnly` `String()` site was introduced in 4c4b23d (v6.11.1); before that, the same input throws at `join`. Every release from v6.7.0 through v6.16.0 is affected.\n### Impact\nAn unauthenticated request can make any code path that re-serializes attacker-influenced data with `qs.stringify` and `arrayFormat: 'comma'` (for example, rebuilding a query string from `req.query` for a redirect or an upstream request, or serializing a parsed JSON body) throw synchronously. In a typical Node.js HTTP framework the throw is caught by the framework error boundary and the affected request returns a 500; the process survives and other requests are unaffected. Where the call runs outside an error boundary, such as an `async` Express 4 handler (where the throw becomes an unhandled promise rejection) or a bare `http` request handler, the process exits, so the impact in that case depends on the application error handling rather than on qs. The default `arrayFormat` (`indices`) is not affected.\nhttps://www.cve.org/CVERecord?id=CVE-2026-110816https://github.com/ljharb/qs/security/advisories/GHSA-6pq8-jhm2-2vcwhttps://github.com/ljharb/qs/commit/a952e7519338ef0cfb25694a2988848f93333727#ljharb #qs#CVE_2026_110816#bot", "url": "https://infosec.exchange/users/cve/statuses/117442194595536272"}, {"timestamp": "2026-10-16T20:17:24.605Z", "date_only": false, "value": "2026-10-16T20:17:24.605809Z", "kind": "other", "label": "Recorded", "source": "cvelistv5 / CISA-ADP", "record": "CVE-2026-110816", "field": "containers.adp.0.metrics.0.other.content.timestamp"}, {"timestamp": "2026-10-16T20:17:24.605Z", "date_only": false, "value": "2026-10-16T20:17:24.605809Z", "kind": "other", "label": "Recorded", "source": "fkie_nvd \u00b7 FKIE_CVE-2026-110816", "record": "FKIE_CVE-2026-110816", "field": "metrics.ssvcV203.0.ssvcData.timestamp"}, {"timestamp": "2026-10-16T20:17:48.588Z", "date_only": false, "value": "2026-10-16T20:17:48.588Z", "kind": "other", "label": "Updated", "source": "cvelistv5", "record": "CVE-2026-110816", "field": "cveMetadata.dateUpdated"}, {"timestamp": "2026-10-16T20:17:48.588Z", "date_only": false, "value": "2026-10-16T20:17:48.588Z", "kind": "other", "label": "Updated", "source": "cvelistv5 / CISA-ADP", "record": "CVE-2026-110816", "field": "containers.adp.0.providerMetadata.dateUpdated"}, {"timestamp": "2026-10-16T21:17:23.953Z", "date_only": false, "value": "2026-10-16T21:17:23.953", "kind": "other", "label": "Updated", "source": "fkie_nvd \u00b7 FKIE_CVE-2026-110816", "record": "FKIE_CVE-2026-110816", "field": "lastModified"}]}