Summary
Seroval: Deserialization invokes attacker-chosen callables: AsyncIteratorFactoryInstance calls source.on(listener) without type check
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.
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.
Workarounds
Avoid plugins whose deserialize returns functions or objects with an on method when decoding untrusted input. Upgrading to 1.6.8 is recommended.
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.
Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect. Typical impact: arbitrary code execution or logic abuse.
CVE-2026-116580 has a CVSS score of 7.3 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.6.8); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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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.
Frequently Asked Questions
- What is CVE-2026-116580? CVE-2026-116580 is a high-severity insecure deserialization vulnerability in seroval (npm), affecting versions <= 1.6.7. It is fixed in 1.6.8. Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect.
- How severe is CVE-2026-116580? CVE-2026-116580 has a CVSS score of 7.3 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of seroval are affected by CVE-2026-116580? seroval (npm) versions <= 1.6.7 is affected.
- Is there a fix for CVE-2026-116580? Yes. CVE-2026-116580 is fixed in 1.6.8. Upgrade to this version or later.
- Is CVE-2026-116580 exploitable, and should I be worried? Whether CVE-2026-116580 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-116580 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-116580? Upgrade
serovalto 1.6.8 or later.