---
id: "CVE-2026-121434"
kind: "vulnerability"
aliases: ["CVE-2026-121434"]
title: "Froxlor: customers with API access can replace managed HTTPS certificates"
severity: "medium"
cvss: 5.4
epss: null
exploited: false
status: "open"
category: "other"
products: []
ecosystems: []
tags: ["froxlor", "hosting", "other", "self-hosted"]
not_affected_if: ["default-config", "no-customer-api-access"]
published_at: "2026-11-03T15:17:34+00:00"
first_seen_at: "2026-11-03T15:22:00+00:00"
updated_at: "2026-11-03T15:23:25+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-121434", "first_seen_at": "2026-11-03T15:22:00+00:00"}]
---

# Froxlor: customers with API access can replace managed HTTPS certificates

Froxlor 2.3.0 before 2.3.15 lacks an authorization check in its Certificates API, so customers can overwrite a domain's Let's Encrypt-managed certificate and private key with their own pair. The attacker-chosen pair is deployed to the web server, which breaks HTTPS for the domain and desynchronizes ACME automation.

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

## How to check

- Check the installed Froxlor version, for example in the admin panel footer or `froxlor/lib/version.php`, and see whether it is before `2.3.15`.
- Check whether customers have API keys enabled for the Certificates API commands.

## Fix

- Froxlor versions from `2.3.0` up to but not including `2.3.15`: move to `2.3.15` or later.

## Timeline

- 2026-11-03T15:22:00+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-121434

## Documents

- [advisory] Vendor advisory: github.com https://github.com/froxlor/froxlor/security/advisories/GHSA-ch7m-649m-x7xg
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/froxlor-2.3.0-before-2.3.15-authorization-bypass-via-certificates-update-api

## From the sources

Froxlor 2.3.0 before 2.3.15 contains a missing authorization check in the Certificates.add and Certificates.update API commands, which do not verify whether a domain's certificate is Let's Encrypt-managed. Customers with API access can overwrite the managed certificate and private key with an attacker-chosen pair, which a REBUILD_VHOST task deploys to the webserver, breaking HTTPS and desynchronizing ACME automation.

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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_