CVE-2026-53653 in Grav
Summary
by MITRE • 07/10/2026
Grav is a file-based Web platform. Prior to 1.7.53 and 2.0.0-rc.8, Grav allows an unauthenticated visitor to exhaust server memory and CPU by requesting image derivatives with oversized dimensions through URL query image actions such as forceResize in Grav::fallbackUrl, which passes request parameters to ImageMedium magic actions without a dimension or pixel ceiling. This issue is fixed in versions 1.7.53 and 2.0.0-rc.8.
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Analysis
by VulDB Data Team • 07/10/2026
This vulnerability exists within the Grav content management platform where unauthenticated users can exploit image processing functionality to consume excessive system resources through crafted URL requests. The flaw specifically affects versions prior to 1.7.53 and 2.0.0-rc.8, making it a critical resource exhaustion vulnerability that could lead to denial of service conditions. The vulnerability stems from the lack of input validation and dimensional constraints in the image derivative generation process.
The technical implementation involves the Grav::fallbackUrl function which processes URL query parameters containing image manipulation commands such as forceResize. These parameters are directly passed to ImageMedium magic actions without proper dimension or pixel limitations, allowing attackers to specify arbitrarily large image dimensions. When the system attempts to generate these oversized image derivatives, it consumes disproportionate amounts of server memory and CPU resources proportional to the requested dimensions, leading to potential system instability or complete service unavailability.
This vulnerability maps to CWE-400 which describes "Uncontrolled Resource Consumption" and aligns with ATT&CK technique T1499.100 for "Application Exhaustion Flood" within the resource consumption category. The attack vector is particularly dangerous because it requires no authentication, making it accessible to any visitor to the website. The impact extends beyond simple denial of service as excessive resource consumption can affect other services running on the same server infrastructure, potentially compromising overall system stability and performance.
The operational implications are significant for organizations relying on Grav platforms, as this vulnerability could be exploited by malicious actors to disrupt services or perform volumetric attacks. Attackers could systematically request images with increasingly larger dimensions until system resources are exhausted, causing cascading failures that impact legitimate users. The fix implemented in versions 1.7.53 and 2.0.0-rc.8 addresses the root cause by introducing dimensional ceilings and proper parameter validation.
Mitigation strategies should include immediate upgrade to patched versions and implementation of additional safeguards such as rate limiting for image processing requests, monitoring for unusual resource consumption patterns, and configuring maximum allowable image dimensions in system configurations. Organizations should also consider implementing web application firewalls with rules to detect and block suspicious image request patterns that exceed normal operational parameters, ensuring comprehensive protection against similar vulnerabilities in the future.