Froxlor before 2.3.12 Command Injection via letsencryptchallengepath

Froxlor before 2.3.12 does not restrict or escape the system.letsencryptchallengepath setting: unlike sibling settings hardened in GHSA-33mp, the field has no string_regexp or required_otp guard, and its value is concatenated unescaped into the acme.sh command line built in lib/Froxlor/Cron/Http/LetsEncrypt/AcmeSh.php and executed by the root cron via FileDir::safe_exec. Because safe_exec only blacklists shell metacharacters such as ; | & > < \ $ ~ ?, spaces and quotes survive and the value is word-split into additional acme.sh arguments. An administrator, or any actor able to write settings (for example through the settings-import API), can therefore inject acme.sh options such as --renew-hook, --pre-hook or --post-hook to obtain arbitrary command execution as root at the next Let's Encrypt cron run, or use --config-home/--cert-home for arbitrary file writes. Versions up to and including 2.3.10 are affected; the issue is fixed in 2.3.12.

Source published

26 Sep 2026 13:24:06 UTC

Source modified

26 Sep 2026 23:07:30 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

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CVSS 4.0 · 9.4 CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

CVSS 3.1 · 9.1 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H