CVE-2025-53604 is a medium-severity vulnerability identified in the pimeys web-push crate for Rust, specifically in versions before 0.10.3. The vulnerability is classified under CWE-130, which pertains to improper handling of length parameter inconsistencies. The issue arises when the web-push crate processes HTTP requests containing a Content-Length header with a large integer value. Due to insufficient validation or improper handling of this length parameter, the built-in clients of the web-push crate can be forced into a denial of service (DoS) condition through excessive memory consumption. This occurs because the system attempts to allocate or process memory based on the large Content-Length value, leading to resource exhaustion. The vulnerability does not impact confidentiality or integrity but affects availability by causing service disruption. Exploitation does not require authentication or user interaction but does require network access to the vulnerable service. The CVSS v3.1 base score is 4.0, reflecting a medium severity level. The attack vector is network-based, with high attack complexity, no privileges required, and no user interaction needed. The scope is changed, indicating that the vulnerability affects components beyond the initially vulnerable component. No known exploits are currently reported in the wild, and no official patches are linked yet, though upgrading to version 0.10.3 or later is implied to remediate the issue.

For European organizations utilizing the pimeys web-push crate in their Rust-based applications, this vulnerability poses a risk of denial of service through memory exhaustion. Such DoS attacks can disrupt web push notification services, potentially impacting customer communications, real-time alerts, or other critical notification mechanisms. This disruption could degrade user experience and operational continuity, especially for service providers relying on push notifications for timely information delivery. While the vulnerability does not compromise data confidentiality or integrity, the availability impact can lead to service outages, affecting business operations and customer trust. Organizations with high reliance on web-push notifications in sectors such as finance, healthcare, or public services may face operational risks. Additionally, the medium CVSS score suggests that while the threat is not critical, it should not be ignored, particularly in environments where resource constraints or high availability are critical. The lack of known exploits reduces immediate risk but does not eliminate the need for proactive mitigation.

European organizations should take the following specific steps to mitigate this vulnerability: 1) Upgrade the pimeys web-push crate to version 0.10.3 or later as soon as it becomes available, as this version addresses the improper handling of the Content-Length header. 2) Implement input validation and sanity checks on HTTP headers, particularly Content-Length, to reject or limit excessively large values before processing. 3) Employ resource usage monitoring and limits at the application and operating system levels to detect and prevent abnormal memory consumption patterns indicative of exploitation attempts. 4) Use Web Application Firewalls (WAFs) or network-level filtering to block suspicious requests with unusually large Content-Length headers. 5) Conduct regular code audits and dependency reviews to identify and remediate similar length parameter handling issues. 6) Prepare incident response plans to quickly address potential DoS events affecting web-push services. These measures go beyond generic advice by focusing on proactive validation, resource control, and layered defense specific to the nature of this vulnerability.