CVE-2026-23957 in seroval
Summary
by MITRE • 01/22/2026
seroval facilitates JS value stringification, including complex structures beyond JSON.stringify capabilities. In versions 1.4.0 and below, overriding encoded array lengths by replacing them with an excessively large value causes the deserialization process to significantly increase processing time. This issue has been fixed in version 1.4.1.
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Analysis
by VulDB Data Team • 01/22/2026
The vulnerability identified as CVE-2026-23957 resides within the seroval library, a JavaScript utility designed to facilitate the stringification of complex data structures beyond the capabilities of standard JSON.stringify operations. This library serves as a critical component in applications requiring robust serialization of intricate object hierarchies, function representations, and other non-standard JavaScript values that traditional JSON parsing cannot adequately handle. The flaw manifests specifically in versions 1.4.0 and earlier, where the deserialization process exhibits significant performance degradation when encountering manipulated array length values during the parsing phase.
The technical implementation of this vulnerability exploits a fundamental weakness in how seroval handles array length validation during deserialization. When an attacker supplies an encoded array with an excessively large length value that exceeds normal processing limits, the library's internal parsing algorithm becomes susceptible to substantial computational overhead. This occurs because the deserialization routine attempts to allocate memory and process array elements based on the inflated length specification, leading to exponential increases in processing time rather than the expected linear scaling. The flaw represents a classic example of a denial of service vulnerability where computational resources are consumed disproportionately to the input size, creating a resource exhaustion scenario that can effectively halt application responsiveness.
From an operational impact perspective, this vulnerability poses significant risks to applications that rely on seroval for data serialization and deserialization operations. The performance degradation can manifest as complete application unresponsiveness or severe latency increases that may exceed acceptable service level agreements. Attackers can exploit this weakness by crafting malicious payloads containing oversized array length specifications, potentially causing cascading failures in systems that depend on timely processing of serialized data. The vulnerability is particularly concerning in high-throughput environments where multiple concurrent requests could simultaneously trigger the performance degradation, leading to widespread service disruption. Organizations utilizing this library in production systems face potential business impacts ranging from degraded user experience to complete service outages.
The mitigation strategy for CVE-2026-23957 involves immediate upgrade to seroval version 1.4.1 or later, which contains the necessary patches to address the array length validation issue. Security teams should conduct comprehensive vulnerability assessments across all systems utilizing this library to identify potential exposure points and implement proper input validation measures. The fix implemented in version 1.4.1 likely includes enhanced bounds checking and more robust array length validation during the deserialization process, preventing the exploitation of oversized array specifications. Additionally, organizations should consider implementing rate limiting and input sanitization mechanisms as defensive measures, particularly in applications processing untrusted data. This vulnerability aligns with CWE-400, which categorizes excessive resource consumption issues, and could be mapped to ATT&CK technique T1499.004 for resource exhaustion attacks. Regular dependency auditing and automated security scanning should be implemented to prevent similar vulnerabilities from emerging in other components of the software supply chain, as the exploitation patterns suggest a broader class of denial of service vulnerabilities in serialization libraries that may require similar remediation approaches.