CVE-2026-41235

Froxlor has an authorization bypass in FTP shell assignment via missing server-side `available_shells` enforcement

Published Jun 4, 2026 CVSS 4.0 · 8.6 High EPSS < 1% KEV · Not listed

Description

Froxlor is open source server administration software. Version 2.3.6 lets administrators configure `system.available_shells` as the approved shell list that customers may assign to FTP users. However, the server-side FTP account handlers do not enforce that whitelist when processing add or edit requests. As a result, an authenticated customer with shell delegation enabled can submit an arbitrary shell such as `/bin/bash` even when the panel UI only offers more restricted choices. In deployments that use the default `nssextrausers` integration, the attacker-controlled shell is then propagated into the system account database, leading to real host shell access. Version 2.3.7 fixes the issue.

Analysis

Technical impact

Froxlor 2.3.6 allows an authenticated customer with shell delegation to assign any shell, bypassing the configured whitelist of system.available_shells. This authorization bypass enables the attacker to specify shells such as /bin/bash, which are then applied to the system account database, granting the user real shell access on the host. The weakness is an improper authorization check, identified as CWE-863.

Affected Systems

The vulnerability affects Froxlor by froxlor version 2.3.6. The fix is contained in release 2.3.7, and earlier versions remain susceptible.

Risk and Exploitability

The flaw carries a CVSS score of 8.6, indicating high severity. EPSS data is unavailable, but the lack of a KEV listing suggests no known public exploits. Because the attacker must be authenticated as a customer and shell delegation must be enabled, the risk is limited to environments where such delegation is enabled and the UI does not enforce the allowed shell list on the server side. Nonetheless, once exploited, the attacker gains system shell access, representing a major confidentiality, integrity, and availability threat.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

froxlor

affected

Version	Status	Constraints
`= 2.3.6`	affected	—

No data.

Vendor Product Versions

Froxlor

Version	Status	Scheme	Platform
`2.3.6`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Upgrade Froxlor to version 2.3.7 or later, which implements the missing server‑side shell whitelist enforcement.
Audit existing FTP user accounts and remove any unauthorized shells that may have been assigned through the bypass, ensuring they align with system.available_shells.
Verify that any new FTP accounts created after the upgrade are restricted to shells defined in system.available_shells, confirming that the authorization check is active.

Generated by OpenCVE AI on June 4, 2026 at 19:21 UTC.

Tracking

Advisories

Source	ID	Title
Github GHSA	GHSA-gcv3-5v9q-fmhh	Froxlor has an authorization bypass in FTP shell assignment via missing server-side `available_shells` enforcement

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact High

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact High

Subsequent System Integrity Impact High

Subsequent System Availability Impact High

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.228% probability within 30 days)

Exploitation poc

Automatable no

Technical Impact total

References

Link	Providers
https://github.com/froxlor/froxlor/releases/tag/2.3.7
https://github.com/froxlor/froxlor/security/advisories/GHSA-gcv3-5v9q-fmhh

History

Jun 8, 2026 7:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}`

Jun 4, 2026 8:45 PM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Froxlor Froxlor froxlor
Vendors & Products		Froxlor Froxlor froxlor

Jun 4, 2026 6:30 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		Froxlor is open source server administration software. Version 2.3.6 lets administrators configure `system.available_shells` as the approved shell list that customers may assign to FTP users. However, the server-side FTP account handlers do not enforce that whitelist when processing add or edit requests. As a result, an authenticated customer with shell delegation enabled can submit an arbitrary shell such as `/bin/bash` even when the panel UI only offers more restricted choices. In deployments that use the default `nssextrausers` integration, the attacker-controlled shell is then propagated into the system account database, leading to real host shell access. Version 2.3.7 fixes the issue.
Title		Froxlor has an authorization bypass in FTP shell assignment via missing server-side `available_shells` enforcement
Weaknesses		CWE-863
References		https://github.com/froxlor/froxlor/releases/tag/2.3.7 https://github.com/froxlor/froxlor/security/advisories/GHSA-gcv3-5v9q-fmhh
Metrics		cvssV4_0 `{'score': 8.6, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P'}`