Fiber is an Express inspired web framework written in Go. In versions 2.52.8 and below, when using Fiber's Ctx.BodyParser to parse form data containing a large numeric key that represents a slice index (e.g., test.18446744073704), the application crashes due to an out-of-bounds slice allocation in the underlying schema decoder. The root cause is that the decoder attempts to allocate a slice of length idx + 1 without validating whether the index is within a safe or reasonable range. If the idx is excessively large, this leads to an integer overflow or memory exhaustion, causing a panic or crash. This is fixed in version 2.52.9.
CVSS Score
7.5
EPSS Score
0.001
Published
2025-08-06
Fiber is an Express-inspired web framework written in Go. Starting in version 2.52.6 and prior to version 2.52.7, `fiber.Ctx.BodyParser` can map flat data to nested slices using `key[idx]value` syntax, but when idx is negative, it causes a panic instead of returning an error stating it cannot process the data. Since this data is user-provided, this could lead to denial of service for anyone relying on this `fiber.Ctx.BodyParser` functionality. Version 2.52.7 fixes the issue.
CVSS Score
7.5
EPSS Score
0.002
Published
2025-05-22