CVE-2026-25891: Fiber has an Arbitrary File Read in Static Middleware on Windows

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-02-24 · updated 2026-06-17
Weakness: CWE-22

Description

Fiber is an Express inspired web framework written in Go. A Path Traversal (CWE-22) vulnerability in Fiber allows a remote attacker to bypass the static middleware sanitizer and read arbitrary files on the server file system on Windows. This affects Fiber v3 through version 3.0.0. This has been patched in Fiber v3 version 3.1.0.

Affected products

gofiber fiber: from 3.0.0 before 3.1.0 — fixed in 3.1.0

How to fix

Upgrade to a fixed version: gofiber fiber 3.1.0. Check the vendor advisory for mitigations.

References

https://github.com/gofiber/fiber/commit/59133702301c2ab7b776dd123b474cbd995f2c86
https://github.com/gofiber/fiber/pull/4064
https://github.com/gofiber/fiber/security/advisories/GHSA-m3c2-496v-cw3v

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