---
id: "CVE-2026-114101"
kind: "vulnerability"
aliases: ["CVE-2026-114101"]
title: "Coraza WAF: multipart filename parsing lets uploads bypass file rules"
severity: "medium"
cvss: 6.3
epss: 0.00198
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["coraza", "go", "package", "self-hosted", "waf"]
not_affected_if: ["no-coraza", "no-file-upload-rules", "no-upload-endpoints"]
published_at: "2026-10-21T01:17:35+00:00"
first_seen_at: "2026-10-23T21:57:28+00:00"
updated_at: "2026-10-25T04:01:24+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-114101", "first_seen_at": "2026-10-23T21:57:28+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-114101", "first_seen_at": "2026-10-24T13:15:54+00:00"}]
---

# Coraza WAF: multipart filename parsing lets uploads bypass file rules

Coraza before 3.8.1 reads multipart upload filenames with Go's mime.ParseMediaType, which silently drops RFC 5987 filename* parameters that use a charset other than utf-8 or us-ascii. An unauthenticated attacker can send a decoy filename while the real name sits in filename*, so the WAF's file rules never see the dangerous name and it reaches a backend that honors filename*.

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

## How to check

- Check the Coraza version in go.mod (for example `grep coraza go.mod`); affected if below `3.8.1`
- Check whether the WAF is in front of an upload endpoint that accepts multipart forms and passes filenames to a backend that reads filename*

## Fix

- Upgrade the Coraza Go module to `3.8.1` or later (`go get github.com/corazawaf/coraza/v3@v3.8.1`)
- Rebuild and redeploy any service or proxy that embeds Coraza, such as a Caddy or Envoy plugin build

## Timeline

- 2026-10-23T21:57:28+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-114101
- 2026-10-24T13:15:54+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-114101

## From the sources

Coraza before 3.8.1 extracts multipart upload filenames with Go's mime.ParseMediaType, which silently ignores RFC 5987 filename* parameters whose charset is not utf-8 or us-ascii. Unauthenticated attackers can send a decoy filename with filename*=iso-8859-1''shell.php, or filename* alone, so FILES-based rules never see the real name, letting dangerous uploads reach backends that honor filename*.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_