Seroval: Code injection through a typed array's own constructor property

### Summary seroval writes a typed array as a call to its constructor. In affected versions, the constructor name in the output is read from a property that data on the value can replace, and it is written without checks. A typed array that received properties from untrusted data can then put arbitrary code into the serialized output. ### Details Version 1.6.0 changed how seroval finds the class of an object, so that objects with their own `constructor` property serialize correctly. Typed arrays still took the constructor name from the value itself, so the name could come from the untrusted property instead of the array's real type. These functions are affected: - `serialize`, `serializeAsync` - `crossSerialize`, `crossSerializeAsync`, `crossSerializeStream` - the `Serializer` class - `compileJSON` `fromJSON` and `fromCrossJSON` are not affected: they only accept the names of the built-in typed arrays. With the `compactArrayBufferViews` option, the same lookup throws a `TypeError` instead of writing code. ### Impact An application is affected only when it serializes a typed array that has an own `constructor` property set from untrusted data. That requires code that copies properties from untrusted objects onto a typed array. This is unusual, so the severity is rated Low, even though the result is script execution in the page that receives the output. ### Patches Fixed in 1.6.11. The constructor name now comes from the array's internal type, which properties on the value cannot change. `compactArrayBufferViews` uses the real type as well. ### Workarounds If you cannot upgrade, do not copy properties from untrusted objects onto typed arrays, or remove an own `constructor` property from a typed array before serializing it.

Source published

28 Oct 2026 21:17:36 UTC

Source modified

28 Oct 2026 21:30:05 UTC

Observed here

28 Oct 2026 21:55:29 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N

Publisher rating · MODERATE