---
id: CVE-2026-100713
title: >-
  Froxlor 2.3.10 and earlier contain a time-of-check time-of-use (TOCTOU) race
  condition in the SSH key synchronization cron
  (lib/Froxlor/Cron/System/SshKeys.php, SshKeys::generateFiles)
summary: >-
  Froxlor 2.3.10 and earlier contain a time-of-check time-of-use (TOCTOU) race
  condition in the SSH key synchronization cron
  (lib/Froxlor/Cron/System/SshKeys.php, SshKeys::generateFiles). The
  containment/symlink validation performed by Fil…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H'
cwe:
  - CWE-367
vendor: froxlor
product: froxlor
affected:
  - froxlor < 2.3.12
published: '2026-09-26'
updated: '2026-09-26'
sourceUpdated: '2026-09-26T14:16:57.180'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-100713'
references:
  - url: 'https://github.com/froxlor/froxlor/security/advisories/GHSA-927x-9jfh-mq42'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/froxlor-before-2.3.12-privilege-escalation-via-ssh-key-sync
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-26T13:33:20.896Z'
---

## Overview

Froxlor 2.3.10 and earlier contain a time-of-check time-of-use (TOCTOU) race condition in the SSH key synchronization cron (lib/Froxlor/Cron/System/SshKeys.php, SshKeys::generateFiles). The containment/symlink validation performed by FileDir::makeCorrectDir()/makeCorrectFile() is done only at check time; the live filesystem path is re-resolved as root at write time (file_put_contents with FILE_APPEND|LOCK_EX, followed by chmod/chown/chgrp), with a database round-trip and file reads in between, and no path or file-descriptor pinning (no O_NOFOLLOW or openat2(RESOLVE_NO_SYMLINKS)). On installations where the non-default setting system.allow_customer_shell=1 grants customers local shell access, a customer can atomically swap their ~/.ssh directory for a symlink after the check and before the write, causing the root-run cron to append the customer's public key to /root/.ssh/authorized_keys and to chown /root/.ssh to the customer, resulting in full root compromise of the panel host. The cron re-runs on every interval, allowing unlimited attempts. This is a residual race that bypasses the check-time fix introduced for GHSA-mq5v-... . The issue is fixed in Froxlor 2.3.12.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.