Next.js is a React framework for building full-stack web applications. Starting in version 10.0.0 and prior to version 16.1.7, the default Next.js image optimization disk cache (/_next/image) did not have a configurable upper bound, allowing unbounded cache growth. An attacker could generate many unique image-optimization variants and exhaust disk space, causing denial of service. This is fixed in version 16.1.7 by adding an LRU-backed disk cache with images.maximumDiskCacheSize, including eviction of least-recently-used entries when the limit is exceeded. Setting maximumDiskCacheSize: 0 disables disk caching. If upgrading is not immediately possible, periodically clean .next/cache/images and/or reduce variant cardinality (e.g., tighten values for images.localPatterns, images.remotePatterns, and images.qualities).
Weakness
The product does not properly control the allocation and maintenance of a limited resource.
Potential Mitigations
Mitigation of resource exhaustion attacks requires that the target system either:
The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.
The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/147.html
- https://cwe.mitre.org/data/definitions/227.html
- https://cwe.mitre.org/data/definitions/492.html