{"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","slug":"CVE-2026-100713","body":"## Overview\n\nFroxlor 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}