CVE-2026-116580

Seroval facilitates JavaScript value stringification, including complex structures beyond JSON.stringify capabilities. Prior to 1.6.8, fromJSON rebuilds an AsyncIteratorFactoryInstance by calling source.on(listener) without requiring source to be a genuine internal stream. With untrusted Seroval input and an application plugin that returns a callable value or an object exposing an on method, a crafted node can reuse an identifier so the deserializer invokes the plugin-produced value. This is an incomplete-fix variant of CVE-2026-59940. The resulting confidentiality, integrity, or availability impact depends on the behavior exposed by the application plugin. This issue is fixed in version 1.6.8.

Seroval facilitates JavaScript value stringification, including complex structures beyond JSON.stringify capabilities. Prior to 1.6.8, fromJSON rebuilds an AsyncIteratorFactoryInstance by calling source.on(listener) without requiring source to be a genuine internal stream. With untrusted Seroval input and an application plugin that returns a callable value or an object exposing an on method, a crafted node can reuse an identifier so the deserializer invokes the plugin-produced value. This is an incomplete-fix variant of CVE-2026-59940. The resulting confidentiality, integrity, or availability impact depends on the behavior exposed by the application plugin. This issue is fixed in version 1.6.8.

Summary

When fromJSON rebuilt an async iterator, it called on() on the iterator's source without checking that the source was a seroval stream. A crafted payload could pick another value as the source, such as a function returned by an application plugin. The deserializer then called that value's on method.

This is a variant of GHSA-mv8w-475r-vwqw. That fix covered the promise and stream control nodes but not the async iterator node.

Impact

An application that passes untrusted input to fromJSON with plugins that return callable values can have those callables invoked during deserialization. What this allows depends on what the plugin's values do.

Affected versions

• Versions up to 1.6.3 accept any value as the source.
• 1.6.4 rejects the reported payload.
• 1.6.5 to 1.6.7 check the source by node type, which a payload can get around by reusing a node id.
• All versions up to 1.6.7 should be treated as affected.

Patches

Fixed in [email protected]. Streams and sequences are now internal class instances. The deserializer checks the source value with instanceof, so plain data and plugin values are rejected no matter which node id they use.

Workarounds

Avoid plugins whose deserialize returns functions or objects with an on method when decoding untrusted input. Upgrading to 1.6.8 is recommended.

Seroval facilitates JavaScript value stringification, including complex structures beyond JSON.stringify capabilities. Prior to 1.6.8, fromJSON rebuilds an AsyncIteratorFactoryInstance by calling source.on(listener) without requiring source to be a genuine internal stream. With untrusted Seroval input and an application plugin that returns a callable value or an object exposing an on method, a crafted node can reuse an identifier so the deserializer invokes the plugin-produced value. This is an incomplete-fix variant of CVE-2026-59940. The resulting confidentiality, integrity, or availability impact depends on the behavior exposed by the application plugin. This issue is fixed in version 1.6.8.

Seroval facilitates JavaScript value stringification, including complex structures beyond JSON.stringify capabilities. Prior to 1.6.8, fromJSON rebuilds an AsyncIteratorFactoryInstance by calling source.on(listener) without requiring source to be a genuine internal stream. With untrusted Seroval input and an application plugin that returns a callable value or an object exposing an on method, a crafted node can reuse an identifier so the deserializer invokes the plugin-produced value. This is an incomplete-fix variant of CVE-2026-59940. The resulting confidentiality, integrity, or availability impact depends on the behavior exposed by the application plugin. This issue is fixed in version 1.6.8.

Summary

When fromJSON rebuilt an async iterator, it called on() on the iterator's source without checking that the source was a seroval stream. A crafted payload could pick another value as the source, such as a function returned by an application plugin. The deserializer then called that value's on method.

This is a variant of GHSA-mv8w-475r-vwqw. That fix covered the promise and stream control nodes but not the async iterator node.

Impact

An application that passes untrusted input to fromJSON with plugins that return callable values can have those callables invoked during deserialization. What this allows depends on what the plugin's values do.

Affected versions

• Versions up to 1.6.3 accept any value as the source.
• 1.6.4 rejects the reported payload.
• 1.6.5 to 1.6.7 check the source by node type, which a payload can get around by reusing a node id.
• All versions up to 1.6.7 should be treated as affected.

Patches

Fixed in [email protected]. Streams and sequences are now internal class instances. The deserializer checks the source value with instanceof, so plain data and plugin values are rejected no matter which node id they use.

Workarounds

Avoid plugins whose deserialize returns functions or objects with an on method when decoding untrusted input. Upgrading to 1.6.8 is recommended.

TuxCare rebuilt seroval to address 1 CVE. Fixed in 1.5.6-tuxcare.5.