The vulnerability resides in the read_metadata_from_safetensors function of modules/sd_models.py within the stable-diffusion-webui application. By manipulating the header length field included in a safetensors file, an attacker can cause the program to attempt to allocate an excessively large amount of memory. This resource allocation can lead to memory exhaustion on the host running the web UI, resulting in degraded performance or a complete denial of service. The flaw is a direct consequence of improper bounds checking and unchecked user input, categorized as CWE-400 and CWE-770.

The issue affects the AUTOMATIC1111 stable-diffusion-webui project up to version 1.10.1. Any installation that has not applied a fix or upgrade beyond this version could be vulnerable if it processes unsanitized safetensors metadata from untrusted sources.

The CVSS score of 5.3 places the vulnerability in the moderate severity range. While EPSS data is not available and it is not listed in the CISA KEV catalog, the remote nature of the exploit and the availability of a public proof‑of‑concept indicate a non‑negligible risk for systems that expose the web UI to external users. An attacker who can supply a crafted safetensors header can trigger the allocation bug remotely, potentially exhausting system resources without authentication.