CVE-2026-104845 in Seroval
Summary
by MITRE • 10/02/2026
Seroval facilitates JS value stringification, including complex structures beyond JSON.stringify capabilities. Prior to 1.6.3, deserializeTypedArray in fromJSON and fromCrossJSON trusts a deserialized source value as an ArrayBuffer and does not bound the serialized element count. An attacker can provide a small untrusted JSON object with a large length value, causing the array-like TypedArray constructor to synchronously allocate the selected number of elements and exhaust CPU or memory while starving the event loop. The offset check does not reject the crafted source because source.byteLength is undefined. DataView reaches a similar unchecked cast but throws rather than allocating, and the issue has no identified confidentiality or integrity impact. This issue is fixed in version 1.6.3.
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Analysis
by VulDB Data Team • 10/02/2026
The vulnerability described involves a critical resource exhaustion flaw within the Seroval library, specifically affecting versions prior to 1.6.3. Seroval is designed to facilitate JavaScript value stringification and deserialization, offering capabilities that extend beyond standard JSON.stringify limitations by handling complex data structures such as TypedArrays. The core of this vulnerability lies in the deserializeTypedArray function, which is invoked during both fromJSON and fromCrossJSON operations. When processing a serialized source value intended to represent an ArrayBuffer or similar typed array structure, the library fails to adequately validate the length parameter provided within that structure before attempting allocation. This lack of bounds checking allows an attacker to supply a maliciously crafted JSON object containing a significantly inflated length field relative to the actual data size or system capabilities.
From a technical perspective, the flaw stems from insufficient validation of the source byte length and element count during deserialization. The code attempts to construct an array-like TypedArray based on the provided length value without verifying if this value is consistent with the available memory or reasonable bounds for the specific type being instantiated. Furthermore, the offset check mechanism fails to reject the crafted input because the source.byteLength property remains undefined in certain contexts, bypassing potential safeguards that might otherwise limit allocation sizes. Consequently, when the TypedArray constructor executes, it synchronously attempts to allocate a massive number of elements as dictated by the attacker-controlled length field. This synchronous operation consumes excessive CPU cycles and memory resources, leading to a denial of service condition where the application becomes unresponsive or crashes due resource starvation.
The operational impact of this vulnerability is primarily centered on availability rather than confidentiality or integrity. By exhausting system resources such as memory or CPU time, an attacker can effectively starve the event loop in Node.js environments or block execution threads in other JavaScript runtimes. This results in a denial of service for legitimate users and services relying on the affected application. While similar unchecked cast issues exist within DataView handling in Seroval, those instances typically result in exceptions being thrown rather than unbounded allocations, thereby limiting their impact to potential crashes without the same degree of resource exhaustion risk. The absence of identified confidentiality or integrity impacts indicates that this vulnerability is strictly a reliability and availability concern, though its severity remains high due to the ease with which it can be triggered remotely if deserialization of untrusted data occurs.
This issue aligns with CWE-400, Uncontrolled Resource Consumption, as the application fails to properly control the allocation of system resources based on external input. In terms of attack patterns, this vulnerability facilitates Denial of Service attacks and may relate to ATT&CK technique T1496, Resource Hijacking, where an attacker consumes computational resources to disrupt service availability. To mitigate this risk, organizations must immediately upgrade Seroval to version 1.6.3 or later, which includes the necessary fixes for bounds checking during TypedArray deserialization. Additionally, developers should implement strict input validation and size limits on any data structures being deserialized from untrusted sources, ensuring that length fields are validated against expected maximums before triggering allocation routines. Adopting a defense-in-depth strategy by limiting memory usage per request or thread can also provide an additional layer of protection against such resource exhaustion attacks.