The vulnerability identified as CVE-2026-22775 affects the sveltejs devalue JavaScript library, specifically versions from 5.1.0 up to 5.6.1. Devalue is used to serialize complex JavaScript values into strings when JSON.stringify is insufficient. The vulnerability is categorized under CWE-405 (Asymmetric Resource Consumption), where the devalue.parse function improperly handles input during the ArrayBuffer hydration process. It expects base64 encoded strings but does not validate this assumption before decoding. When fed with crafted inputs that violate this expectation, the function can enter resource-intensive processing loops or consume excessive memory, resulting in a denial of service due to CPU exhaustion or memory depletion. This flaw is exploitable remotely without authentication or user interaction, as it only requires an attacker to supply malicious input to the vulnerable parsing function. The vulnerability has a CVSS 3.1 score of 7.5, indicating high severity, with an attack vector of network, low attack complexity, no privileges required, and no user interaction needed. The scope is unchanged, and the impact is limited to availability, with no confidentiality or integrity impact. The vulnerability is fixed in version 5.6.2 of devalue. No known exploits have been observed in the wild, but the potential for denial of service attacks exists, especially in web applications that parse untrusted data using this library.

For European organizations, the primary impact is the risk of denial of service attacks against web applications or services that utilize vulnerable versions of the sveltejs devalue library. Such attacks could lead to service outages, degraded performance, or resource exhaustion on critical infrastructure, affecting availability and potentially causing business disruption. Industries relying heavily on web-based user interfaces or real-time data processing—such as finance, e-commerce, healthcare, and government services—may experience operational interruptions. Additionally, organizations with public-facing applications that accept user-supplied data for processing are at higher risk. While the vulnerability does not compromise confidentiality or integrity, the availability impact can indirectly affect customer trust and regulatory compliance, especially under the EU’s stringent service continuity and data protection regulations. The absence of known exploits reduces immediate risk, but the ease of exploitation and network accessibility make timely remediation critical to prevent potential attacks.

European organizations should immediately identify all instances of the sveltejs devalue library in their software stacks, particularly versions between 5.1.0 and 5.6.1. The primary mitigation is to upgrade to version 5.6.2 or later, where the vulnerability is patched. For applications where immediate upgrade is not feasible, implement input validation and sanitization to ensure that only properly base64-encoded strings are passed to devalue.parse, thereby preventing malformed inputs from triggering excessive resource consumption. Employ rate limiting and Web Application Firewall (WAF) rules to detect and block suspicious requests that could exploit this vulnerability. Monitoring application performance and resource usage can help detect anomalous spikes indicative of an attack. Additionally, conduct code reviews and dependency audits to identify and remediate other potential vulnerabilities in third-party libraries. Finally, maintain an incident response plan to quickly address any denial of service incidents related to this vulnerability.