CVE-2026-22774 is a vulnerability classified under CWE-405 (Asymmetric Resource Consumption) found in the sveltejs devalue library, a JavaScript tool used for serializing complex values beyond JSON.stringify capabilities. Versions from 5.3.0 up to 5.6.1 contain a flaw in the devalue.parse function, which is responsible for deserializing strings back into JavaScript values. The vulnerability arises because the function attempts to hydrate typed arrays by assuming the input is an ArrayBuffer without validating this assumption. Maliciously crafted inputs can exploit this by causing the function to allocate excessive memory or consume disproportionate CPU resources, resulting in a denial of service (DoS) condition. This can be triggered remotely without any authentication or user interaction, simply by submitting specially crafted data to an application using the vulnerable devalue.parse. The impact is limited to availability, as confidentiality and integrity are not affected. The vulnerability has a CVSS 3.1 score of 7.5, indicating high severity. The issue was publicly disclosed on January 15, 2026, and fixed in version 5.6.2 of the library. No known exploits have been reported in the wild yet. Organizations using sveltejs devalue in web applications that accept external input should consider this a critical risk for service disruption.

For European organizations, the primary impact of CVE-2026-22774 is the potential for denial of service attacks against web applications or services that utilize the vulnerable versions of sveltejs devalue to parse untrusted input. This can lead to service outages, degraded performance, and potential loss of availability for end users. Industries relying heavily on web applications with real-time or high-availability requirements, such as financial services, e-commerce, healthcare, and government services, could face operational disruptions. Additionally, organizations providing SaaS or cloud services based in Europe may experience reputational damage and customer trust erosion if their services become unavailable due to exploitation of this vulnerability. While the vulnerability does not directly compromise data confidentiality or integrity, the availability impact alone can have significant business consequences, including regulatory scrutiny under GDPR if service disruptions affect user rights or critical infrastructure. The ease of remote exploitation without authentication increases the risk profile for European entities.

The primary mitigation is to upgrade all instances of the sveltejs devalue library to version 5.6.2 or later, where the vulnerability is patched. Organizations should conduct an inventory of applications and services using devalue.parse to identify affected versions. In addition to upgrading, implement strict input validation and sanitization on all external data before it reaches the parsing function to reduce the risk of malicious payloads triggering excessive resource consumption. Employ runtime resource monitoring and rate limiting on endpoints that accept serialized input to detect and throttle abnormal CPU or memory usage patterns indicative of an attack. Consider deploying Web Application Firewalls (WAFs) with custom rules to block suspicious payloads targeting the devalue.parse function. For critical systems, implement redundancy and failover mechanisms to maintain availability in case of DoS attempts. Finally, maintain up-to-date threat intelligence feeds to monitor for emerging exploits targeting this vulnerability.