Prior to version v1.20230419.0, the FormData API implementation was subject to an integer overflow. If a FormData instance contained more than 2^31 elements, the forEach() method could end up reading from the wrong location in memory while iterating over elements. This would most likely lead to a segmentation fault, but could theoretically allow arbitrary undefined behavior. In order for the bug to be exploitable, the process would need to be able to allocate 160GB of RAM. Due to this, the bug was never exploitable on the Cloudflare Workers platform, but could theoretically be exploitable on deployments of workerd running on machines with a huge amount of memory. Moreover, in order to be remotely exploited, an attacker would have to upload a single form-encoded HTTP request of at least tens of gigabytes in size. The application code would then have to use request.formData() to parse the request and formData.forEach() to iterate over this data. Due to these limitations, the exploitation likelihood was considered Low. A fix that addresses this vulnerability has been released in version v1.20230419.0 and users are encouraged to update to the latest version available.
Published 2023-05-12 11:15:13
Updated 2023-05-26 18:52:35
View at NVD,
Vulnerability category: OverflowMemory Corruption

Exploit prediction scoring system (EPSS) score for CVE-2023-2512

Probability of exploitation activity in the next 30 days EPSS Score History
~ 48 %
Percentile, the proportion of vulnerabilities that are scored at or less

CVSS scores for CVE-2023-2512

Base Score Base Severity CVSS Vector Exploitability Score Impact Score Score Source First Seen
Cloudflare, Inc.

CWE ids for CVE-2023-2512

  • The product reads data past the end, or before the beginning, of the intended buffer.
    Assigned by: (Secondary)
  • The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control.
    Assigned by: (Primary)

References for CVE-2023-2512

Products affected by CVE-2023-2512

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