froxlor: Improper Neutralization of CRLF Sequences
CVE-2026-100717 is a critical-severity improper neutralization of CRLF sequences vulnerability in froxlor, with a CVSS 3.1 base score of 9.9 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists version 2.3.12 as the first without the flaw, so updating froxlor to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.3% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update froxlor to 2.3.12 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- LowSome restricted data can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:H. Scored by CNA (vulncheck.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.5 | High | CNA (vulncheck.com) |
| CVSS 3.1 | 9.9 | Critical | CNA (vulncheck.com) |
Official description
froxlor is a server administration panel. In versions 2.3.10 and earlier, Validate::validateUrl rejects carriage return and line feed characters only in the path, query and fragment components returned by parse_url, and never inspects the userinfo (user:pass@) components. This is an incomplete fix for GHSA-c3p2. An authenticated low-privilege customer with subdomain-create rights (no admin or change_serversettings privilege required) can supply a subdomain redirect URL that carries a CR/LF payload in the userinfo portion (e.g. http://user%0areturn 200 "pwned";%[email protected]/). The value passes validation, survives IDNA encoding, and is written verbatim into the generated nginx or Apache vhost configuration, allowing the attacker to break out of the emitted directive and inject arbitrary web-server configuration lines. froxlor regenerates and reloads the web-server configuration as root, so the injected directives take effect server-wide and can hijack responses or read local files. The issue is fixed in version 2.3.12.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of CRLF Sequences
The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.
How developers prevent this class of flaw
- Appropriately filter or quote CRLF sequences in user-controlled input.
More Improper Neutralization of CRLF Sequences vulnerabilities (CWE-93)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in froxlor
- 7.2 High severity
- 9.9 Critical severity
- 8.5 High severity
- 7.7 High severity
- 8.7 High severity
- 7.1 High severity
Recent Improper Neutralization of CRLF Sequences vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.2 High severity
- 8.8 High severity
- 7.5 High severity
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