CVE-2026-23957
Published: 22 January 2026
Summary
CVE-2026-23957 is a high-severity Allocation of Resources Without Limits or Throttling (CWE-770) vulnerability in Lxsmnsyc Seroval. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 8.2th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
Threat & Defense at a Glance
Threat & Defense Details
Likely Mitigating ControlsAI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
This control implements explicit throttling on session allocation, addressing the weakness of allocating resources without limits.
Plan testing exercises resource allocation limits and throttling during simulated failures, directly addressing weaknesses that allow unbounded resource use.
Contingency plan updates ensure recovery strategies address unbounded resource allocation, making it harder for attackers to exploit lack of throttling to cause prolonged outages.
Provides continuity when unbounded resource allocation at the primary site leads to exhaustion and downtime.
Alternate services allow operations to continue when primary allocation of resources lacks limits or throttling.
Explicit planning of security-related actions requires defining limits, windows, and resource allocations, making allocation without throttling far less likely.
Measures of performance include tracking allocation behavior and throttling effectiveness, reducing the window for resource exhaustion attacks.
Imposes an inactivity-based limit on network resource allocation, throttling the number of concurrently held connections.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Vuln enables remote unauthenticated exploitation of public-facing apps (T1190) via malicious serialized payloads, directly causing endpoint DoS through application/system exploitation (T1499.004).
NVD Description
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…
more
been fixed in version 1.4.1.
Deeper analysisAI
CVE-2026-23957 is a denial-of-service vulnerability in the seroval JavaScript library, which enables serialization of JavaScript values including complex structures beyond standard JSON.stringify capabilities. In versions 1.4.0 and below, attackers can override encoded array lengths in serialized data by replacing them with excessively large values, causing the deserialization process to consume significant processing time due to resource exhaustion (CWE-770). The vulnerability carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
Any remote, unauthenticated attacker can exploit this vulnerability by crafting and delivering malicious serialized payloads to applications that use affected seroval versions for deserialization. Successful exploitation leads to substantial increases in CPU usage during deserialization, potentially resulting in denial of service for the targeted application or service without requiring user interaction.
The issue has been addressed in seroval version 1.4.1. Official mitigation guidance is available in the GitHub security advisory at https://github.com/lxsmnsyc/seroval/security/advisories/GHSA-66fc-rw6m-c2q6 and the fixing commit at https://github.com/lxsmnsyc/seroval/commit/ce9408ebc87312fcad345a73c172212f2a798060; security practitioners should upgrade to the patched version and validate input serialization/deserialization processes.
Details
- CWE(s)