---
id: "GHSA-3wr7-993q-jrff"
kind: "vulnerability"
aliases: ["GHSA-3wr7-993q-jrff", "GO-2026-6691"]
title: "Coraza: Multipart filename* (RFC 5987) charset restriction lets a decoy filename bypass FILES-based rules in github.com/corazawaf/coraza"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: [{"name": "github.com/corazawaf/coraza", "fixed": [], "affected": "all versions", "ecosystem": "go"}, {"name": "github.com/corazawaf/coraza/v2", "fixed": [], "affected": "all versions", "ecosystem": "go"}, {"name": "github.com/corazawaf/coraza/v3", "fixed": ["3.8.1"], "affected": "< 3.8.1", "ecosystem": "go"}]
ecosystems: ["go"]
tags: ["coraza", "go", "package", "self-hosted", "waf"]
not_affected_if: ["no-multipart-file-rules", "version-3.8.1-or-later"]
published_at: "2026-10-19T21:08:17+00:00"
first_seen_at: "2026-10-23T19:13:08+00:00"
updated_at: "2026-10-23T20:15:32+00:00"
sources: [{"source": "govuln", "url": "https://pkg.go.dev/vuln/GO-2026-6691", "first_seen_at": "2026-10-23T19:13:08+00:00"}]
---

# Coraza: Multipart filename* (RFC 5987) charset restriction lets a decoy filename bypass FILES-based rules in github.com/corazawaf/coraza

Coraza, a Go web application firewall library, mishandles multipart filename* (RFC 5987) parameters so a crafted decoy filename can slip past FILES-based rules. An attacker can smuggle a malicious upload through a WAF that inspects uploaded filenames.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- go:github.com/corazawaf/coraza affected all versions fixed ?
- go:github.com/corazawaf/coraza/v2 affected all versions fixed ?
- go:github.com/corazawaf/coraza/v3 affected < 3.8.1 fixed 3.8.1

## How to check

Check the go.mod of each service for github.com/corazawaf/coraza/v3 and confirm the version is below 3.8.1.
Run go list -m github.com/corazawaf/coraza/v3 to see the resolved version.

## Fix

Upgrade github.com/corazawaf/coraza/v3 to 3.8.1 or later.

## Timeline

- 2026-10-23T19:13:08+00:00 govuln https://pkg.go.dev/vuln/GO-2026-6691

## From the sources

Coraza: Multipart filename* (RFC 5987) charset restriction lets a decoy filename bypass FILES-based rules in github.com/corazawaf/coraza

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