---
id: "CVE-2026-114426"
kind: "vulnerability"
aliases: ["CVE-2026-114426"]
title: "SEPPmail Secure Email Gateway: unauthenticated upload flaw lets attackers exhaust resources"
severity: "high"
cvss: 8.7
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["email-gateway", "infrastructure", "self-hosted", "seppmail"]
not_affected_if: ["version-15.1.1-or-later"]
published_at: "2026-11-04T09:17:41+00:00"
first_seen_at: "2026-11-04T09:26:09+00:00"
updated_at: "2026-11-04T09:26:47+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-114426", "first_seen_at": "2026-11-04T09:26:09+00:00"}]
---

# SEPPmail Secure Email Gateway: unauthenticated upload flaw lets attackers exhaust resources

SEPPmail Secure Email Gateway before 15.1.1 processes and writes v1 file-interface upload data before checking the caller's identity, and it has no absolute request-size limit. An unauthenticated remote attacker can tie up workers and fill temporary storage with concurrent or slow requests, making the service unavailable.

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

## How to check

- Check the installed SEPPmail version against the fixed release `15.1.1`
- Confirm whether the v1 file-interface upload endpoint is reachable from the internet

## Fix

- SEPPmail Secure Email Gateway: upgrade to `15.1.1` or later

## Timeline

- 2026-11-04T09:26:09+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-114426

## From the sources

SEPPmail Secure Email Gateway before 15.1.1 processes and writes v1 file-interface upload data before authenticating the caller and without an absolute request-size limit. An unauthenticated remote attacker can occupy workers and consume temporary storage with concurrent or slow requests, causing service unavailability.

---

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