Buffer under-read in workerd

CVE-2023-2512

What is CVE-2023-2512?

An integer overflow issue has been identified in the FormData API of Cloudflare's Workerd prior to version v1.20230419.0. This vulnerability can arise when a FormData instance exceeds 2^31 elements, causing the forEach() method to potentially read from incorrect memory locations. While a segmentation fault is likely, the vulnerability is capable of resulting in various undefined behaviors. Although operational constraints mean it’s not practically exploitable on the Cloudflare Workers platform, the risk persists in environments where workerd is deployed on systems with significant memory allocation. To exploit the vulnerability, an attacker would need to upload exceptionally large form-encoded HTTP requests suitable for triggering the flaw, requiring substantial resources. Users are strongly advised to upgrade to the patched version v1.20230419.0.

References