Fiber panics when fiber.Ctx.BodyParser parses invalid range index

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

7.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P · score source

EPSS

• CVE-2025-48075: 0.53% estimated exploitation activity in the next 30 days; percentile 44.74 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary When using the fiber.Ctx.BodyParser to parse into a struct with range values, a panic occurs when trying to parse a negative range index Details fiber.Ctx.BodyParser can map flat data to nested slices using key[idx]value syntax, however 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 Reproducing Take a simple GoFiberV2 server which returns a JSON encoded version of the FormData Correct Behaviour Send a valid request such as: You recieve valid JSON Crashing behaviour Send an invalid request such as: The server panics and crashes Impact Anyone using fiber.Ctx.BodyParser can/will have their servers crashed when an invalid payload is sent

Published by the source

22 May 2025, 20:08 UTC

Last modified by the source

28 May 2025, 19:46 UTC

Source last checked

26 Oct 2026, 15:09 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-hg3g-gphw-5hhm

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# Patch Next advisory brief: CVE-2025-48075

Advisory: Fiber panics when fiber.Ctx.BodyParser parses invalid range index
IDs: CVE-2025-48075, GHSA-hg3g-gphw-5hhm
Record: https://patchnext.com/advisories/cve-2025-48075 (revision 1, source checked 26 Oct 2026, 15:09 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/gofiber/fiber/v2 2.52.7. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/gofiber/fiber/v2: affected >= 2.52.6, < 2.52.7; fixed in 2.52.7

## Suggested inspection (read-only)
- Go github.com/gofiber/fiber/v2: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/gofiber/fiber/v2.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-hg3g-gphw-5hhm (GitHub-reviewed advisory GHSA-hg3g-gphw-5hhm lists affected ranges: Go github.com/gofiber/fiber/v2 >=2.52.6 <2.52.7)

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